2018年美国“数学大联盟杯赛”(中国赛区)初赛三年级试卷及答案

2017-2018年度美国“数学大联盟杯赛”（中国赛区）题目翻译及解题tips【翻译】：2018与以下哪个数字相加的总和是偶数？The sum of…总和…；the even number偶数【翻译】：约翰和吉尔一共有92美元。

约翰的钱是吉尔的三倍。

问约翰有多少钱？①…has three times（倍数）as many(修饰可数名词)/much(修饰不可数名词)as…A的…是B的几倍②As···as···和什么一样多【翻译】：汤姆是一个篮球热爱者！在他的书中，他写了100次“ILOVENBA”（我爱NBA）。

问他写的第500个字母是什么。

（提示：本题考查周期循环规律题）【翻译】：一个长*宽为8*25的长方形和以下哪个长方形有相同的面积。

【翻译】：前100个正整数（1-100）的和与后50个正整数（51-100）的和之间的差是多少？①Positive difference···与···的差；②positive integers正整数【翻译】：你有一根10英尺长的杆子需要被切成10等份。

若每一份需要10秒去切，完成这份工作一共需要多少秒。

【翻译】：Amy将2018四舍五入约至十位（rounded···to the nearest tens）得到的数字与Ben将2018四舍五入约至百位得到的数字，这两个数字之和是多少？【翻译】：下列哪组数有最小公倍数？【翻译】：Dan每买2支铅笔的同时也会5支钢笔。

如果他买了10支铅笔，那他一共买了几支钢笔？【翻译】：星期四的20天后是星期几？【翻译】：下列哪个角的度数最小？①an obtuse钝角②an acute锐角③a right直角④a stright平角【翻译】：我们班的每位学生都要轮流喊一个整数。

第一个人喊的是1。

2017-2018年度美国“数学大联盟杯赛”(中国赛区)初赛(四年级)(初赛时间：2017年11月26日，考试时间90分钟，总分200分)学生诚信协议：考试期间，我确定没有就所涉及的问题或结论，与任何人、用任何方式交流或讨论，我确定我所填写的答案均为我个人独立完成的成果，否则愿接受本次成绩无效的处罚。

请在装订线内签名表示你同意遵守以上规定。

考前注意事项：1. 本试卷是四年级试卷，请确保和你的参赛年级一致；2. 本试卷共4页(正反面都有试题)，请检查是否有空白页，页数是否齐全；3. 请确保你已经拿到以下材料：本试卷(共4页，正反面都有试题)、答题卡、答题卡使用说明、英文词汇手册、草稿纸。

考试完毕，请务必将英文词汇手册带回家，上面有如何查询初赛成绩、及如何参加复赛的说明。

其他材料均不能带走，请留在原地。

选择题：每小题5分，答对加5分，答错不扣分，共200分，答案请填涂在答题卡上。

1.Which of the following is the smallest?A) 2.018 B) 20.18 C) 0.218 D) 20182.What is the least common multiple of 20 and 18?A) 90 B) 180 C) 240 D) 3603.The sum of the degree-measures of the exterior angles of a triangle is?A) 180 B) 360 C) 540 D) 7204.In the figure on the right, please put the numbers 1 – 11 in the elevencircles so that the three numbers in every straight line add up to 18.What is the number in the middle circle? Note: There are 5 straightlines in total in this figure.A) 6 B) 7 C) 8 D) 95.I am a lovely cat. When I multiply the digits of a whole numberand the product I get is 8, I put that whole number on my list offavorite numbers. Of the whole numbers from 1000 to 9999,how many would I put on my list of favorite numbers?A) 10 B) 12 C) 16 D) 206.Two planes take off at the same time from the same point to race to apoint and back. Place A travels at 180 miles per hour on the way out and240 miles per hour on the return trip. Plane B covers the entire distance at an averagespeed of 210 miles per hour. Which plane wins the race, or is it a tie?A) plane A wins B) plane B winsC) a tie D) non-deterministic 7.52 × 88 = 44 ×?A) 102 B) 96 C) 104 D) 1248.What is the smallest whole number that leaves a remainder of 4, 5, 6 when divided byeach of 5, 6, 7?A) 29 B) 209 C) 210 D) 20099.In △ABC, m∠A + m∠C = m∠B. What is the degree measure of ∠B?A) 80 B) 90 C) 100 D) 18010.I bought a toy for $10, sold it for $20, rebought it for $30, and resold it for $40. My totalprofit on the 4 transactions was ?A) 10 B) 20 C) 30 D) 4011.What is the greatest number of integers I can choose from the first ten positive integers sothat any 3 of the chosen integers could be the lengths of the three sides of a triangle?A) 4 B) 5 C) 6 D) 712.How many whole numbers between 200 and 400 have all their digits increasing in valuewhen read from left to right?A) 30 B) 36 C) 42 D) 4813.What is the value of 1% of 10% of 100?A) 0.01 B) 0.1 C) 1 D) 1014.If three cats can eat three bowls of food in three minutes, how many minutes will it take100 cats to eat 100 bowls of food?A) 1 B) 3C) 100 D) None of the above15.There are three squares. The area of the smallest one is 2. The side-length of the secondsquare is twice the side-length of the smallest one. And the side-length of the third square is three-times the side-length of the smallest one. The total area of the three squares isA) 12 B) 28 C) 36 D) 7216.A man, who had been married for three years, spent25of his yearly income on his family,14on business, and110on personal travel. If he saved $45000 during those three years, what was his annual income?A) $45000 B) $50000C) $65000 D) None of the above17.Given four different integers, at most how many different sums can be formed bychoosing two, three, or four of them and finding each sum?A) 8 B) 9 C) 10 D) 1118. Max places 100 eggs in 10 baskets, with each basket receiving at least1 egg, but no2 baskets receiving the same number of eggs. What is the greatest number of eggs that may be placed in a basket?A) 45 B) 47 C) 55 D) 6519. 2 + 3 × 4 – 5 =A) 0 B) 6 C) 9 D) 15 20. What is the highest power of 2 that divides 2 × 4 × 6 × 8 × 10? A) 25 B) 27 C) 28 D) 215 21. Which of the following is a prime number?A) 2017B) 2018C) 2015D) 201622. What is the greatest possible number of acute angles in a figure consisting of a triangleand a line passing through two sides of the triangle?A) 5B) 6C) 7D) 823. Amy can solve 5 questions every 3 minutes. Kate can solve 3 questions every 5 minutes.How many more questions Amy can solve than Kate in one hour?A) 15B) 32C) 60D) 6424. Using 3 Ts and 2 Js, in how many different orders can the five letters be arranged? Forexample, TTTJJ and TTJJT are two such different orders.A) 2B) 10C) 20D) 6025. Coastal Coconuts can divide all their coconuts evenly among 8, 9, or10 customers, with 1 coconut left over each time. If Coastal Coconuts has more than 1 coconut, what is the least number of coconuts they could have?A) 561 B) 721C) 831 D) None of the above 26. 35 ÷ 32 =A) 3 B) 9 C) 27 D) 81 27. If the sum of three prime numbers is 30, what is the least prime number?A) 2B) 3C) 5D) 728. Juxtaposing two identical squares to form a rectangle, the perimeter of the rectangle is 12less than the sum of the perimeter of the two squares. What is the side-length of the original square?A) 3B) 6C) 9D) 1229. It takes Mike 2 hours to finish a task. It takes 4 hours for Tom to finish the same task.Mike and Tom worked together on this task for one hour before Mike had to leave. How long will it take Tom to finish the rest of the task?A) 1 B) 2 C) 3 D) 4 30. The number of triangles in the figure on the right isA) 9 B) 10 C) 11 D) 12 31. What is the thousands digit of the product 1234560 × 2345670 × 3456780?A) 8B) 6C) 5D) 032. The sum of nine consecutive positive integers is always divisible byA) 2B) 5C) 7D) 933. You can put as many as 96 books in 6 backpacks. How many backpacks are necessary for144 books?A) 7B) 8C) 9D) 1034. The number of nickels I have is twice the number of dimes I have, and together thesecoins are worth more than $1. The least number of dimes that I can have isA) 5B) 6C) 8D) 1035. The ages of four kids are four consecutive positive integers. The product of their ages is3024. How old is the oldest kid?A) 8B) 9C) 10D) 1136. In the Game of Life, you earn 3 points for flipping a coin to “heads”, and 5 points forflipping a coin to “tails”. In all, how many positive whole number scores are IMPOSSIBLE to get after flipping it one or more times?A) 4B) 5C) 7D) 1137. Four monkeys can eat four bags of peanuts in three minutes. How many monkeys will ittake to eat 100 bags of peanuts in one hour?A) 4 B) 5 C) 20 D) 100 38. The tens digit of the product of the first 100 positive integers isA) 2B) 4C) 8D) 039. Someone put three dimes into my pile of quarters. If I add up the value of these coins,including the dimes, the sum could beA) $6.25B) $7.75C) $8.05D) $9.5040. Brooke's empty tub fills in 20 minutes with the drain plugged, andher full tub drains in 10 minutes with the water off. How manyminutes would it take the full tub to drain while the water is on?A) 12B) 15 C) 20 D) 30。

2017-2018年度美国“数学大联盟杯赛”(中国赛区)初赛(三年级)(初赛时间：2017年11月26日，考试时间90分钟，总分200分)学生诚信协议：考试期间，我确定没有就所涉及的问题或结论，与任何人、用任何方式交流或讨论，我确定我所填写的答案均为我个人独立完成的成果，否则愿接受本次成绩无效的处罚。

请在装订线内签名表示你同意遵守以上规定。

考前注意事项：1. 本试卷是三年级试卷，请确保和你的参赛年级一致；2. 本试卷共4页(正反面都有试题)，请检查是否有空白页，页数是否齐全；3. 请确保你已经拿到以下材料：本试卷(共4页，正反面都有试题)、答题卡、答题卡使用说明、英文词汇手册、草稿纸。

考试完毕，请务必将英文词汇手册带回家，上面有如何查询初赛成绩、及如何参加复赛的说明。

其他材料均不能带走，请留在原地。

选择题：每小题5分，答对加5分，答错不扣分，共200分，答案请填涂在答题卡上。

1. 5 + 6 + 7 + 1825 + 175 =A) 2015 B) 2016 C) 2017 D) 20182.The sum of 2018 and ? is an even number.A) 222 B) 223 C) 225 D) 2273.John and Jill have $92 in total. John has three times as much money as Jill. How muchmoney does John have?A) $60 B) $63 C) $66 D) $694.Tom is a basketball lover! On his book, he wrote the phrase “ILOVENBA” 100 times.What is the 500th letter he wrote?A) L B) B C) V D) N5.An 8 by 25 rectangle has the same area as a rectangle with dimensionsA) 4 by 50 B) 6 by 25 C) 10 by 22 D) 12 by 156.What is the positive difference between the sum of the first 100 positive integers and thesum of the next 50 positive integers?A) 1000 B) 1225 C) 2025 D) 50507.You have a ten-foot pole that needs to be cut into ten equal pieces. If it takes ten secondsto make each cut, how many seconds will the job take?A) 110 B) 100 C) 95 D) 908.Amy rounded 2018 to the nearest tens. Ben rounded 2018 to the nearest hundreds. Thesum of their two numbers isA) 4000 B) 4016 C) 4020 D) 4040 9.Which of the following pairs of numbers has the greatest least common multiple?A) 5,6 B) 6,8 C) 8,12 D) 10,2010.For every 2 pencils Dan bought, he also bought 5 pens. If he bought 10 pencils, how manypens did he buy?A) 25 B) 50 C) 10 D) 1311.Twenty days after Thursday isA) Monday B) Tuesday C) Wednesday D) Thursday12.Of the following, ? angle has the least degree-measure.A) an obtuse B) an acute C) a right D) a straight13.Every student in my class shouted out a whole number in turn. The number the firststudent shouted out was 1. Then each student after the first shouted out a number that is 3 more than the number the previous student did. Which number below is a possible number shouted out by one of the students?A) 101 B) 102 C) 103 D) 10414.A boy bought a baseball and a bat, paying $1.25 for both items. If the ball cost 25 centsmore than the bat, how much did the ball cost?A) $1.00 B) $0.75 C) $0.55 D) $0.5015.2 hours + ? minutes + 40 seconds = 7600 secondsA) 5 B) 6 C) 10 D) 3016.In the figure on the right, please put digits 1-7 in the sevencircles so that the three digits in every straight line add upto 12. What is the digit in the middle circle?A) 3 B) 4 C) 5 D) 617.If 5 adults ate 20 apples each and 3 children ate 12 apples in total, what is the averagenumber of apples that each person ate?A) 12 B) 14 C) 15 D) 1618.What is the perimeter of the figure on the right? Note: Allinterior angles in the figure are right angles or 270°.A) 100 B) 110C) 120 D) 16019.Thirty people are waiting in line to buy pizza. There are 10 peoplein front of Andy. Susan is the last person in the line. How manypeople are between Andy and Susan?A) 18 B) 19C) 20 D) 2120.Thirty-nine hours after 9:00 AM isA) 1:00 AM B) 12:00 PM C) 8:00 PM D) 12:00 AM21.200 + 400 + 600 + 800 = (1 + 2 + 3 + 4) ×?A) 2 B) 20 C) 200 D) 200022.11…11 (the number consisting of 2016 1’s) is not a mult iple ofA) 11 B) 111 C) 1111 D) 1111123.The average of two thousands and two millions isA) 10000 B) 1000000 C) 1001000 D) 111100024.A triangle has the same area as a square. If the length of a base of the triangle is the sameas the side-length of the square, and the height of the triangle to the base is 4, what is thearea of the square?A) 1/2 B) 2 C) 4 D) 825.When V olta found a field in the shape of an isosceles triangle, she was soexcited that she ran a lap around all three sides. Two sides of the field havelengths of 505 m each, and the third side has a whole-number length.What is the greatest possible distance that V olta might have run in one lap?A) 2016 B) 2017 C) 2018 D) 201926.25 ×66 = 75 ×?A) 22 B) 44 C) 16 D) 3327.The number that has an odd number of whole number divisors isA) 15 B) 16 C) 17 D) 1828.In a sequence of 8 numbers, the average of the 8 terms is 15. If the average of the firstthree terms is 16 and the average of the next two terms is 15, what is the average of thelast three terms?A) 12 B) 13 C) 14 D) 1529.All years between 2000 and 2050 that are divisible by 4 are leap years.No other years between 2000 and 2050 are leap years. How many daysare there all together in the 17 years from 2010 to 2026?A) 6029 B) 6030 C) 5018 D) 501930.The sum of the hundreds digit and the tens digit of 2357 isA) 5 B) 8 C) 10 D) 1231.Which of the expressions below has the greatest value of (quotient × remainder)?A) 27 ÷ 4 B) 47 ÷ 6C) 57 ÷ 8 D) 87 ÷ 1232.I have some dimes and nickels, and together these coins are worth $3. If I replace everynickel with a quarter, I will have $5. How many dimes do I have?A) 10 B) 15 C) 20 D) 2533.I am a lovely cat. When I multiply the digits of a whole numberand the product I get is 9, I put that whole number on my list offavorite numbers. Of the whole numbers from 1000 to 9999, howmany would I put on my list of favorite numbers?A) 5 B) 10 C) 15 D) 2034.The sum of the tens digit and the units digit of the sum 1 + 12 + 123 + 12345+ … + 123456789 isA) 4 B) 5 C) 6 D) 735.The product of all prime numbers between 1 and 10 isA) 210 B) 105C) 1890 D) none of the above36.What is the average of 12, 14, 16, and 18?A) 13 B) 14 C) 15 D) 1637.When Jon shouts out a whole number, Al shouts out the product ofits digits, Barb shouts out the product of the digits of the number Alshouted out, and Cy shouts out the product of the digits of thenumber Barb shouted out. When Cy shouts out 18, what numbermight Jon have shouted out?A) 789 B) 799 C) 899 D) 99938.Each big box contains 3 medium boxes, each medium box contains2 small boxes, and each small box contains 5 apples. How many bigboxes are necessary for 1200 apples?A) 30 B) 40 C) 50 D) 6039.Eighteen years from now, my age will be 4 more than twice my currentage. My age now isA) 12 B) 14 C) 16 D) 1840.Each time Wanda waved her wand, 4 more stars appeared on herdress (which started with no stars). After several waves, Wandamultiplied the total number of stars then on her dress by thenumber of times she had waved her wand. This product cannot beA) 144 B) 256 C) 364 D) 676。

2013-2014年度美国“数学大联盟杯赛”（中国赛区）初赛（八、九年级）一、选择题（每小题5分，答对加5分，答错不扣分，共150分，答案请填涂在答题卡上）1. Eil can ’t figure out how that desk got under his elephant! If the elephant ’s weight in kg is a power of 8, the ones digit of the weight in kg could be.A)0 B)3 C)6 D)92. If I multiply a divisor of 24 by a divisor of 35, the product could not beA)1 B)42 C)56 D)663. A rectangle is 4 times as long as it is wide. If its perimeter is 40, what is its area?A)100 B)64 C)40 D)244. Sophia ’s average score after 6 tests was 82. Her average score on the 7th and 8th tests was a 98. What is her average score for all 8 tests?A)86 B)88 C)90 D)945. How many integers from 1 through 1000 have 0 as at least one digit?A)162 B)171 C)180 D)1816. Five distinct points were chosen on a circle and every possible pair of these points was connected by a line segment. The interior of the circle is divided into ? regions.A)18 B)16 C)15 D)117. When I divide one integer by another, the quotient is 27.18. Which of the following could be the remainder when I do the same division?A)12 B)24 C)36 D)488. The least integer greater than 1 that leaves a remainder of 1when divided by each integer 2,3,4,5,6,7,8,and 9 is betweenA)2 and 1000 B)1000 and 2000 C)2000 and 3000 D)3000 and 40009. Mr. Zilch ’s pocket just became empty. Nine minutes ago, his pocket was exactly half full. He was putting coins into it at a rate that would have filled this empty pocket in 36 minutes. A hole in his pocket was leaking coins at a rate that would have emptied his full pocket in ? minutes.A)12 B)18 C)36 D)7210. We mixed some of my ore that is 10% gold with some of your ore that is 15% gold. We got1.8kg of ore that contained 228 g of pure gold. The mix included how many grams of my ore?A)820 B)840 C)880 D)96011. What is the sum of the roots of ?x x --=264320A)2 B)6 C)18 D)4212. The product of the slopes of two perpendicular lines may equal A)1 B)4 C)-1D)-4 13. When I expand the product ()()()()()x x x x x ---++21012and combine all like terms, my polynomial has exactly how many terms?A)6 B)5 C)4 D)314. The Fergusons are counting pairs of lovebirds form a hot air balloon. Over 5 days they see totals of n, ,,n n n +++123, and n +4 pairs, for a total of 360 birds. The value of n isA)34 B)35 C)70 D)14015. Speedy the snail moves x cm per hour. How many cm does Speedy move in y 10minutes? A)x y600 B)xy 6 C)xy 6 D)y x 600 16. If the x -and y -intercepts of a line have equal nonzero values, then the slope of the line must beA)0 B)even C)positive D)negative17. If x ◆()y x y xy =+-2, then what is the value of 4◆2?A)16 B)28 C)32 D)3618. A square of side-lengthπhas the same area as a circle of radiusA)1 B)π C)π D)π2 19. If x is an integer, which of the following must be divisible by3?A)()()()x x x +++124B)()()()x x x +++245 C)()()()x x x +++346 D)()()()x x x +++46820. Patches the clown has 120 balloons, of which 5% are blue. If he lets 90 of the balloons go but keeps all the blue ones, then ? of the remaining balloons will be blue.A)15% B)20% C)25% D)30% 21. If x -=-114, then x -2= A)-12 B)-16 C)116 D)1222. If ()n -=2181, then ? could be the value of n -4.A)-14 B)-12 C)-10 D)-823. What is the x -intercept of a line that passes through the points (2,2) and (-4,4)?A)(0,-8) B)(8,0) C)(,)803 D)(,)-80324. Points ,,P Q R , and S lie on a straight line, in that order. Q is exactly halfway between P and S , and R is exactly halfway between Q and .S If the distance form Q to R is x cm and the distance form P to Q is x -46cm, what is the distance from P to ?SA)2cm B)3cm C)6cm D)12cm25. Detective Marlon Phillow is on the case, detecting how many students are in his science class. Of two science classes at the school, his class had an average score of 82 on the final exam, the other calss had an average of 86, and both classes combined had an average of 85. The other calss has 60 students, so Marlon ’s class has ? students.A)20 B)30 C)40 D)4526. If x and y are primes andxy ⨯⨯⨯⨯3557is a rational number, then x y +must equalA)10B)13 C)18 D)21 27. If x ⨯=⨯316145210, then x =A)30B)31 C)60 D)61 28. When x 7 is divided by 10 the remainder is 1. Of the following, which could be the value ofx ?A)21 B)22 C)24 D)2529. +++++++=10010010010110210210310333333333 A)1043 B) 1053 C) 1103 D) 910330. A hot dog eating champion had an amazing day and set a new world record by eating x hot dogs in ten minutes. If x is the unique solution to x bx -+=2298000, then what is the valueof b ?A)-140 B)70 C)280 D)490 二、填空题（每小题5分，答对加5分，答错不扣分，共50分，答案请填涂在答题卡上）31. There are n positive integers. Every integer has the same prime factors as 2013 has.The product of any two of these n integers is not a perfect square . What is the maximum value of n ?Answer: .32. ,,,,a b c d e and f are 6 different numbers between 1 and 9. .ab cd ef += ab and cd are prime numbers. ef has 12 factors. What is the maximum possible value of ?ab cd ⨯ Answer: .33. The least common multiple of four distinct positive integers is the same as the sum of the four numbers. If the second largest number is 105, what is the smallest number?Answer: .34. The sum of 5 different prime numbers is 200. Each of the 5 prime numbers is less than 100. Four of the 5 prime numbers have the same units digit. What is the median of the 5 prime numbers?Answer: .35. The sum of the digits of 2014 is 2+0+1+4=7. For how many numbers between 1 and 10000 is the sum of the digits of each number 29?Answer: .36. Tom has 6 cards with number 1 on each card, 3 cards with number 2 on each card, 5 cards with number 3 on each card, 1 card with number 5 it, 3 cards with number 7 on each card, and 2 cards with number 9 on each card. So Tom has 20 cards in total. He uses all these 20 cards to form 12 different prime numbers. Each primer number is either a number on a card, or a number from concatenating the two numbers on two cards. (Card with number 9 can ’t be used as number 6, and vice versa.) The product of all the 12 prime numbers is ab cd 207381348. What is abcd ? Answer: .37. Ten people stand to form a line, ,p 1,p 2,p 3,p 4,p 5,p 6,p 7,p 8,p 9,p 10with p 1 the leftmost person. Some of them are truth-tellers who always speak the truth. And the rest are all liars who always lie.p 1stated that there are 3 liars to my right. p 2stated that there are is one liars to my left. p 3stated that there are 4 liars to my right. p 4stated that there are is one liars to my left. p 5stated that there are 5 liars to my right. p 6stated that there are 9 liars in total.p 7stated that there are 2 liars to my right. p 8stated that there are 6 liars to my left. p 9stated that there are 5 liars to my left. p 10stated that there are 3 liars to my left. How many truth-tellers are there?Answer: .38. n S denotes the sum of all the digits of integer n . For example, .S =++=1231236 Two different integers m and n form a pair, <,m n >, where <,<,<m n m n 100100, and .m n m S n S +=+ How many such pairs, <,m n >, exist?Answer: .39. Place numbers 14,27,36,57,178,467,590, and 2345 on the eight vertexes of an octagon such that any two numbers on two adjacent vertexes share some same digit (s).What is the sum of the two numbers adjacent to 57?Answer: .40. If a 4-digit number, which is a perfect square, can be written as aabb cc -, it is called a “good ” perfect square number. How many “good ” perfect square numbers are there?Answer: .。

2014-2015年度美国”数学大联盟杯赛“（中国赛区）初赛（十、十一、十二年级）一、选择题（每小题10分，答对加10分，答错不扣分，共100分，请将正确答案A 、B 、C 或者D 写在每题后面的圆括号内。

）正确答案填写示例如下：=-⨯⨯20522 ？ （A ）A)5 B)15 C)25 D)301. Meg loves her megaphone! The large circular end has a circumference that is the reciprocal of its diameter. What is the area of the circle? ( )A)π14 B) π12 C) 14 D) 122. How many solutions does the equation x x +=233 have? ( )A)0 B)1 C)2 D)43. If y x =-1, which of the following is always true for any value of x ? ( )A) ()()x y -=-2211B) ()()x x y y -=-222211 C) ()()x x y y --=-222211 D) ()()()()x x y y -+=-+22221111 4. Lee the crow ate a grams of feed that was 1% seed, b grams of feed that was 2% seed, and c grams of feed that was 3% seed. If combined, all the feed he ate was 1.5% seed. What is a in terms of b and c ?( )A)b c +3B)b c +3 C)b c +23 D)b c +32 5. If <x 0 and <.x 2001, then x -1 must be ( )A)less than -10B)between-0.1 and 0 C)between 0and 0.1 D) greater than 106. At 9:00 A.M., the ratio of red to black cars in a parking lot was 1 to 5. An hour later the number of red cars had increased by 2, the number of black cars had decreased by 5, and the ratio of red to black cars was 1 to 4. How many black cars were in the lot at 10:00 A.M.? ( )A)13 B)15 C)60 D)657. If x ≠1and x ≠-1, then ()()()x x x x x --++-32241111=( ) A)x -21 B) x +21 C) x -241 D) x -341 8. The Camps are driving at a constant rate. At noon they had driven 300 km.At 3:30 P.M. they had driven 50% further than they had driven by 1:30 P.M.What is their constant rate in km/hr? ( )A)150 B)120 C)100 D)909. The letters in DIGITS can be arranged in how many orders without adjacent I ’s? ( )A)240 B)355 C)600 D)71510. Al, Bea, and Cal each paint at constant rates, and together they are painting a house. Al and Bea togethercould do the job in 12 hours; Al and Cal could to it in 15, and Bea and Cal could do it in 20. How many hours will it take all three working together to paint the house?( )A)8.5 B)9 C)10 D)10.5二、填空题（每小题10分，答对加10分，答错不扣分，共200分）11. What is the sum of the degree-measures of the angles at the outer points ,,,A B C D and E of a five-pointed star, as shown? Answer: . 12. What is the ordered pair of positive integers (,k b ), with the least value of k , which satisfiesk b ⋅⋅=34234?Answer: .13. A face-down stack of 8 playing cards consisted of 4 Aces (A ’s) and 4 Kings (K ’s).After I revealed and then removed the top card, I moved the new top card to thebottom of the stack without revealing the card. I repeated this procedure until thestack without revealing the card. I repeated this procedure until the stack was leftwith only 1 card, which I then revealed. The cards revealed were AKAKAKAK ,in that order. If my original stack of 8 cards had simply been revealed one card at atime, from top to bottom (without ever moving cards to the bottom of the stack),in what order would they have been revealed?Answer: .14. For what value of a is one root of ()x a x a -+++=222120 twice the other root?Answer: .15. Each time I withdrew $32 from my magical bank account, the account ’sremaining balance doubled. No other account activity was permitted. My fifth$32 withdrawal caused my account ’s balance to become $0. With how manydollars did I open that account?Answer: .16. In how many ways can I select six of the first 20 positive integers, disregarding the order in which these sixintegers are selected, so that no two of the selected integers are consecutive integers?Answer: .17. If, for all real ,()()xx f x f x =-21, what is the numerical value of f (3)?Answer: .18. How many pairs of positive integers (without regard to order) have a least common multiple of 540?Answer: .19. If the square of the smaller of consecutive positive integers is x , what is the square of the larger of thesetwo integers, in terms of x ?Answer: .20. A pair of salt and pepper shakers comes in two types: identical and fraternal.Identical pairs are always the same color. Fraternal pairs are the same colorhalf the time. The probability that a pair of shakers is fraternal is p andthat a pair is identical is .q p =-1 If a pair of shakers is of the same color, AE DCBword 格式-可编辑-感谢下载支持 determine, in terms of the variable q alone, the probability that the pair is identical. Answer: .21. As shown, one angle of a triangle is divided into four smaller congruentangles. If the lengths of the sides of this triangle are 84, 98, and 112, as shown,how long is the segment marked x ?Answer: .22. How long is the longer diagonal of a rhombus whose perimeter is 60, if threeof its vertices lie on a circle whose diameter is 25, as shown?Answer: .23. The 14 cabins of the Titanic Mail Boat are numbered consecutively from1 through 14, as are the 14 room keys. In how many different ways canthe 14 room keys be placed in the 14 rooms, 1 per room, so that, for everyroom, the sum of that room ’s number and the number of the key placed inthat room is a multiple of 3?Answer: .24. For some constant b , if the minimum value of ()x x b f x x x b -+=++2222is 12, what is the maximum value of ()f x ? Answer: .25. If the lengths of two sides of a triangle are 60cos A and 25sin A , what is the greatest possible integer-length of the third side?Answer: .26. {}n a is a geometric sequence in which each term is a positive number. If a a =5627, what is the value oflog log log ?a a a +++3132310Answer: . 27. What is the greatest possible value of ()=sin cos ?f x x x ++3412Answer: .28. Let C be a cube. Triangle T is formed by connecting the midpoints of three edges of cube C . What is the greatest possible measure of an angle of triangle T ?Answer: .29. Let a and b be two real numbers. ()sin f x a x b x =++34 and (lg log )f =3105. What is the value of (lg lg )f 3?Answer: .30. Mike likes to gamble. He always bets all his chips whenever the number of chips he has is <=5. He always bets n （10-）chips whenever the number of chips he has is greater than 5 and less than 10. He continues betting until either he has no chips or he has more than 9 chips. For every round, if he bets n chips. The probability that he wins or loses in each round is 50%. If Mike begins with 4 chips, what is the probability that he loses all his chips?Answer: .1129884xword格式-可编辑-感谢下载支持。

2014年美国“数学大联盟杯赛”（中国赛区）初赛三、四年级详解2013-2014年度美国“数学大联盟杯赛”(中国赛区)初赛答案(三、四年级)一、选择题1. A.Since 0 is a factor, 2 × 0 × 1 × 4 = 0.A) 0B) 7C) 8D) 20142. B.If 2 years ago I was 3 years old, I am now 3 + 2 = 5.A) 4B) 5C) 6D) 233. D.8 + (60 ÷ 4) = 8 + (15) = 23.A) 15B) 17C) 22D) 234. B.(1 + 7) + (2 + 6) + (3 + 5) = 3 × 8 = 24 = 4 + 20.A) 4B) 20C) 24D) 285. C.The prime numbers less than 10 are 2, 3, 5, and 7.A) 2B) 3C) 4D) 56. B.Caleb the dog dreams he has 12 dozen bones. Since 12 dozen = 12 × 12 = 144, there are 144 ÷ 2 = 72 pairs. Caleb will have to dig 72 holes.A) 24B) 72C) 144D) 2887. C.From 9:45 PM to 10:45 PM is 60 mins. From 10:45 PM to 11 PM is 15 mins. From 11 PM to 11:10 PM is 10 mins. That’s (60 +15 + 10) mins.A) 65B) 75C) 85D) 958. D.From January 1st to January 31st, there are 16 odd-numbered dates. From February 1st to February 21st, there are11 odd-numbered dates. That’s 27 × $2 = $54.A) $48B) $50C) $52D) $549. C.9 × 9 + 9 × 8 + 9 × 7 + 9 × 6 = 9 × (9 + 8 + 7 + 6).A) 20B) 24C) 30D) 3610.D.Manny weighs three times as much as Murray. Manny also weighs 8000 kg more than Murray, so 8000 kg is twice Murray’s weight. Thus Murray weighs 4000 kg and Manny weighs 12 000 kg.D) 12 00011.B.I have twice as many shirts as hats, and four times as many hats as scarves. If I have 24 shirts, I have 24÷ 2 = 12 hats and 12 ÷ 4 = 3 scarves.A) 2B) 3C) 6D) 1212.C.My coins have a total value of $6.20. If I have 1 of each coin, I have (1 + 5 + 10 + 25)￠= 41￠. Subtract 41￠from $6.20 repeatedly until there is 5￠ left. After 15 subtractions, there is 5￠left. I have 15 + 5 or20 pennies.A) 10B) 15C) 20D) 2513.D.The diagrams demonstrate choices A, B, and C.A) 14 kmB) 10 kmC) 8 kmD) 1 km14.C.(2014 ?1014) + (3014 ? 2014) = 1000 + 1000 = 2000.A) 0B) 1000C) 2000D) 201415.A.10 + (9 ×8) ? (7 × 6) = 10 + 72 ? 42 = 40.A) 40B) 110The prime factorization of 72 is 2 × 2 × 2 × 3 × 3. The largest prime is 3.A) 3B) 7C) 36D) 7217.D.6 × 4 = 24 = 96 ÷ 4.A) 6B) 12C) 24D) 9618.C.If 6 cans contain 96 teaspoons of sugar, 1 can contains 96 ÷ 6 = 16 teaspoons of sugar. Thus 15 cans contain 16 × 15 = 240 teaspoons of sugar.A) 192B) 208C) 240D) 28819.C.The largest possible such sum is 98 + 99 = 197.A) 21B) 99C) 197D) 19820.B.Ann sent Wilson hearts with odd numbers with odd tens digits. The number on each heart he received must be two digits with both digits odd. There are 5 possible tens digits and 5 possible ones digits.That’s a total of 5 × 5 = 25 hearts.A) 23B) 25C) 30D) 4521.B.Since Rich ate his favorite sandwich 8 days ago, today is the 9th day of the month. Since the shortest month has 28 days, it is at least 28 ? 9 = 19 days until the last day of the month. He must wait 1 more day.A) 1922.D.The factors of 49 are 1, 7, and 49. Since 49 has 3 factors, it has a prime number of factors.A) 6B) 12C) 36D) 4923.D.Dividing a certain two-digit number by 10 leaves a remainder of 9, so it is 19, 29, 39, 49, 59, 69, 79, 89, or 99. The only number listed with remainder 8 when divided by 9 is 89, so the number is89 and 8 + 9 = 17.A) 7B) 9C) 13D) 1724.A.The whole numbers less than 1000 that can be written as such a product are 0 × 1 × 2, 1 × 2 × 3, 2 × 3 ×4, 3 × 4 × 5, 4 × 5 × 6, 5 × 6 × 7, 6 × 7 × 8, 7 × 8 × 9, 8 × 9 × 10, and 9 × 10 ×11. In all, that’s 10.A) 10B) 11C) 15D) 2125.B.The only such numbers are 5432, 5431, 5430, 5421, 5420, 5410, 5321, 5320, 5310, and 5210. In all, there are 10 such numbers.A) 3B) 10C) 69D) 12026.C.2014 × 400 = 805 600; the hundreds digit is 6.A) 0B) 5C) 6D) 827.B.Greta was 110 cm tall 2 years ago, when she was 10 cm taller than her brother. Her brother was 100 cmB) 130C) 140D) 15028.B.The number 789 678 567 456 is added to the number 987 876 765 654. Since we carry a 1 when adding the left-most digits, the sum has 12 + 1 digits.A) 12B) 13C) 24D) 2529.D.We must find which number among the choices is two more than a multiple of 5. Divide each choice by5 (or recogniz e that any number that ends in “2”or “7” is 2 more than a multiple of 5).A) 4351B) 5215C) 5616D) 646230.C.Of every 11 people, there are 2 adults and 9 children. Since99 ÷ 11 = 9, there are 9 groups of 11 people.Of these, 9 × 2 = 18 are adults.A) 9B) 11C) 18D) 22二、填空题31.5.32.22.33.4.34.1.35.617.36.21.37.499.38.765.39.69.40.10.。

2017-2018年度美国“数学大联盟杯赛”(中国赛区)初赛(十、十一、十二年级)(初赛时间：2017年11月26日，考试时间90分钟，总分300分)学生诚信协议：考试期间，我确定没有就所涉及的问题或结论，与任何人、用任何方式交流或讨论，我确定我所填写的答案均为我个人独立完成的成果，否则愿接受本次成绩无效的处罚。

请在装订线内签名表示你同意遵守以上规定。

考前注意事项：1. 本试卷是十、十一、十二年级试卷，请确保和你的参赛年级一致；2. 本试卷共4页(正反面都有试题)，请检查是否有空白页，页数是否齐全；3. 请确保你已经拿到以下材料：本试卷(共4页，正反面都有试题)、答题纸、英文词汇手册、草稿纸。

考试完毕，请务必将英文词汇手册带回家，上面有如何查询初赛成绩、及如何参加复赛的说明。

其他材料均不能带走，请留在原地。

填空题(每小题10分，答对加10分，答错不扣分，共300分。

)1.Each pirate wants his own treasure chest, but there is 1 more pirate than thereare treasure chests. If the pirates would agree to pair up so each pirateshares a treasure chest with another pirate, then 1 treasure chest wouldnot be assigned to any pirate. How many treasure chests are there?Answer: ________________.2.If m and nare positive integers that satisfy 10=, what is the greatest possiblevalue of m + n?Answer: ________________.3.There are an infinite number of points with positive coordinates(x,y) the sum of whose coordinates is the square of an integer.Among all such points (x,y), which one satisfies y = 2x and hasx as small as possible?Answer: ________________.4.As shown, a small square is inscribed in one of the triangles formed whenboth diagonals of a larger square are drawn. If the area of the larger squareis 144, what is the area of the smaller square?Answer: ________________.5.Trisection points on opposite sides of a rectangle are joined, as shown. Ifthe area of the shaded region is 2018, what is the area of the rectangle?Answer: ________________.6. A unit fraction is a fraction whose numerator is 1 and whosedenominator is a positive integer. What is the largest rationalnumber that can be written as the sum of 3 different unitfractions?Answer: ________________.7.What is the greatest possible perimeter of a rectangle whose length and width are differentprime numbers, each less than 120?Answer: ________________.8.Mom, Dad, and I each write a positive integer. My number is leastand Dad's is greatest. The average of all 3 numbers is 20. Theaverage of the 2 smallest numbers is 8. If Dad's number is d andif my number is m, what is the greatest possible value of d–m?Answer: ________________.9.If 8 different integers are chosen at random from the first 15 positive integers, what is theprobability that an additional number chosen at random from the remaining 7 positiveintegers is smaller than every one of the 8 originally chosen positive integers?Answer: ________________.10.What sequence of 5 positive integers has these three properties:1) All but one of the numbers is a multiple of 5.2) Every number after the first is 1 more than the sum of all the preceding numbers.3) The first number is as small as possible.Answer: ________________.11.Three beavers (one not shown) take turns biting a tree until it falls. Thesecond beaver is twice as likely as the first to make the tree fall. Thethird is twice as likely as the second to make the tree fall. What isthe probability that a bite taken by the third beaver causes thetree to fall?Answer: ________________.12.What is the ratio, larger to smaller, of a rectangle's dimensions if halfof the rectangle is similar to the original rectangle?Answer: ________________.第1页，共4页第2页，共4页A rectangle is partitioned into 9 different squares, as shown at the right. The area of the smallest square, shown fully darkened, is 1. Two other squares have areas of 196 and 324, as shown. What is the area of the shaded square? Answer: ________________.When the square of an eight-digit integer is subtracted from the square of a differenteight-digit integer, the difference will sometimes have eight identical even digits. What are both possible values of the repeated digit in such a situation? Answer: ________________.If the perimeter of an isosceles triangle with integral sides is 2017, how many different lengthsare possible for the legs? Answer: ________________.What are all ordered triples of positive primes (p ,q ,r ) which satisfy p q + 1 = r ? Answer: ________________.The reflection of (6,3) across the line x = 4 is (2,3). If m ≠ 4, what is the reflection of (m ,n )across the line x = 4? Answer: ________________.The vertices of a triangle are (8,7), (0,1), and (8,1). What are thecoordinates of all points inside this triangle that have integralcoordinates and lie on the bisector of the smallest angle of the triangle? Answer: ________________.In a regular 10-sided polygon, two pairs of different vertices (four different verticesaltogether) are chosen at random, so that all points chosen are distinct from each other. What is the probability that the line segments determined by each pair of points do not intersect? Answer: ________________.A line segment is drawn from the upper right vertex of aparallelogram, as shown, dividing the opposite side into segments with lengths in a 2:1 ratio. If the area of the parallelogram is 90, what is the area of the shaded region?Answer: ________________.21. If 0 < a ≤ b ≤ 1, what is the maximum value of ab 2 – a 2b ? Answer: ________________.22. What are all ordered pairs of integers (x ,y ) that satisfy 5x 3 + 2xy – 23 = 0? Answer: ________________.23. If two altitudes of a triangle have lengths 10 and 15, what is the smallest integer that couldbe the length of the third altitude?Answer: ________________.24. If h is the number of heads obtained when 4 fair coins are each tossed once, what is theexpected (average) value of h 2? Answer: ________________.25. What is the largest integer N for which 7x + 11y = N has no solution in non-negativeintegers (x ,y )? Answer: ________________.26. There are only two six-digit integers n greater than 100 000 for which n 2 has n as its finalsix digits (or, equivalently, for which n 2 – n is divisible by 106). One of the integers is 890 625. What is the other?Answer: ________________.27. A hexagon is inscribed in a circle as shown. If lengths of three sidesof the hexagon are each 1 and the lengths of the other three sides are each 2, what is the area of this hexagon? Write your answer in its exact format or round to the nearest tenth. Answer: ________________.28. If x is a number chosen uniformly at random between 0 and 1, what is the probability thatthe greatest integer ≤ 21log x ⎛⎫⎪⎝⎭ is odd?Answer: ________________.29. In the interval -1 < x < 1, sin θ is one root of x 4 – 4x 3 + 2x 2 – 4x + 1 = 0. In that sameinterval, for what ordered pair of integers (a ,b ) is cos 2θ one root of x 2 + ax + b = 0? Answer: ________________.30. Let P (x ) = 2x 10 + 3x 9 + 4x + 9. If z is a non-real solution of z 3 = 1, what is the numericalvalue of 23111P P P z z z ⎛⎫⎛⎫⎛⎫++ ⎪ ⎪ ⎪⎝⎭⎝⎭⎝⎭?Answer: ________________.第3页，共4页第4页，共4页。

2017-2018年度美国“数学大联盟杯赛”(中国赛区)初赛(三年级)(初赛时间：2017年11月26日，考试时间90分钟，总分200分)学生诚信协议：考试期间，我确定没有就所涉及的问题或结论，与任何人、用任何方式交流或讨论，我确定我所填写的答案均为我个人独立完成的成果，否则愿接受本次成绩无效的处罚。

请在装订线内签名表示你同意遵守以上规定。

考前注意事项：1. 本试卷是三年级试卷，请确保和你的参赛年级一致；2. 本试卷共4页(正反面都有试题)，请检查是否有空白页，页数是否齐全；3. 请确保你已经拿到以下材料：本试卷(共4页，正反面都有试题)、答题卡、答题卡使用说明、英文词汇手册、草稿纸。

考试完毕，请务必将英文词汇手册带回家，上面有如何查询初赛成绩、及如何参加复赛的说明。

其他材料均不能带走，请留在原地。

选择题：每小题5分，答对加5分，答错不扣分，共200分，答案请填涂在答题卡上。

1. 5 + 6 + 7 + 1825 + 175 =A) 2015 B) 2016 C) 2017 D) 20182.The sum of 2018 and ? is an even number.A) 222 B) 223 C) 225 D) 2273.John and Jill have $92 in total. John has three times as much money as Jill. How muchmoney does John have?A) $60 B) $63 C) $66 D) $694.Tom is a basketball lover! On his book, he wrote the phrase “ILOVENBA” 100 times.What is the 500th letter he wrote?A) L B) B C) V D) N5.An 8 by 25 rectangle has the same area as a rectangle with dimensionsA) 4 by 50 B) 6 by 25 C) 10 by 22 D) 12 by 156.What is the positive difference between the sum of the first 100 positive integers and thesum of the next 50 positive integers?A) 1000 B) 1225 C) 2025 D) 50507.You have a ten-foot pole that needs to be cut into ten equal pieces. If it takes ten secondsto make each cut, how many seconds will the job take?A) 110 B) 100 C) 95 D) 908.Amy rounded 2018 to the nearest tens. Ben rounded 2018 to the nearest hundreds. Thesum of their two numbers isA) 4000 B) 4016 C) 4020 D) 4040 9.Which of the following pairs of numbers has the greatest least common multiple?A) 5,6 B) 6,8 C) 8,12 D) 10,2010.For every 2 pencils Dan bought, he also bought 5 pens. If he bought 10 pencils, how manypens did he buy?A) 25 B) 50 C) 10 D) 1311.Twenty days after Thursday isA) Monday B) Tuesday C) Wednesday D) Thursday12.Of the following, ? angle has the least degree-measure.A) an obtuse B) an acute C) a right D) a straight13.Every student in my class shouted out a whole number in turn. The number the firststudent shouted out was 1. Then each student after the first shouted out a number that is 3 more than the number the previous student did. Which number below is a possible number shouted out by one of the students?A) 101 B) 102 C) 103 D) 10414.A boy bought a baseball and a bat, paying $1.25 for both items. If the ball cost 25 centsmore than the bat, how much did the ball cost?A) $1.00 B) $0.75 C) $0.55 D) $0.5015.2 hours + ? minutes + 40 seconds = 7600 secondsA) 5 B) 6 C) 10 D) 3016.In the figure on the right, please put digits 1-7 in the sevencircles so that the three digits in every straight line add upto 12. What is the digit in the middle circle?A) 3 B) 4 C) 5 D) 617.If 5 adults ate 20 apples each and 3 children ate 12 apples in total, what is the averagenumber of apples that each person ate?A) 12 B) 14 C) 15 D) 1618.What is the perimeter of the figure on the right? Note: Allinterior angles in the figure are right angles or 270°.A) 100 B) 110C) 120 D) 16019.Thirty people are waiting in line to buy pizza. There are 10 peoplein front of Andy. Susan is the last person in the line. How manypeople are between Andy and Susan?A) 18 B) 19C) 20 D) 2120.Thirty-nine hours after 9:00 AM isA) 1:00 AM B) 12:00 PM C) 8:00 PM D) 12:00 AM21.200 + 400 + 600 + 800 = (1 + 2 + 3 + 4) ×?A) 2 B) 20 C) 200 D) 200022.11…11 (the number consisting of 2016 1’s) is not a mult iple ofA) 11 B) 111 C) 1111 D) 1111123.The average of two thousands and two millions isA) 10000 B) 1000000 C) 1001000 D) 111100024.A triangle has the same area as a square. If the length of a base of the triangle is the sameas the side-length of the square, and the height of the triangle to the base is 4, what is thearea of the square?A) 1/2 B) 2 C) 4 D) 825.When V olta found a field in the shape of an isosceles triangle, she was soexcited that she ran a lap around all three sides. Two sides of the field havelengths of 505 m each, and the third side has a whole-number length.What is the greatest possible distance that V olta might have run in one lap?A) 2016 B) 2017 C) 2018 D) 201926.25 ×66 = 75 ×?A) 22 B) 44 C) 16 D) 3327.The number that has an odd number of whole number divisors isA) 15 B) 16 C) 17 D) 1828.In a sequence of 8 numbers, the average of the 8 terms is 15. If the average of the firstthree terms is 16 and the average of the next two terms is 15, what is the average of thelast three terms?A) 12 B) 13 C) 14 D) 1529.All years between 2000 and 2050 that are divisible by 4 are leap years.No other years between 2000 and 2050 are leap years. How many daysare there all together in the 17 years from 2010 to 2026?A) 6029 B) 6030 C) 5018 D) 501930.The sum of the hundreds digit and the tens digit of 2357 isA) 5 B) 8 C) 10 D) 1231.Which of the expressions below has the greatest value of (quotient × remainder)?A) 27 ÷ 4 B) 47 ÷ 6C) 57 ÷ 8 D) 87 ÷ 1232.I have some dimes and nickels, and together these coins are worth $3. If I replace everynickel with a quarter, I will have $5. How many dimes do I have?A) 10 B) 15 C) 20 D) 2533.I am a lovely cat. When I multiply the digits of a whole numberand the product I get is 9, I put that whole number on my list offavorite numbers. Of the whole numbers from 1000 to 9999, howmany would I put on my list of favorite numbers?A) 5 B) 10 C) 15 D) 2034.The sum of the tens digit and the units digit of the sum 1 + 12 + 123 + 12345+ … + 123456789 isA) 4 B) 5 C) 6 D) 735.The product of all prime numbers between 1 and 10 isA) 210 B) 105C) 1890 D) none of the above36.What is the average of 12, 14, 16, and 18?A) 13 B) 14 C) 15 D) 1637.When Jon shouts out a whole number, Al shouts out the product ofits digits, Barb shouts out the product of the digits of the number Alshouted out, and Cy shouts out the product of the digits of thenumber Barb shouted out. When Cy shouts out 18, what numbermight Jon have shouted out?A) 789 B) 799 C) 899 D) 99938.Each big box contains 3 medium boxes, each medium box contains2 small boxes, and each small box contains 5 apples. How many bigboxes are necessary for 1200 apples?A) 30 B) 40 C) 50 D) 6039.Eighteen years from now, my age will be 4 more than twice my currentage. My age now isA) 12 B) 14 C) 16 D) 1840.Each time Wanda waved her wand, 4 more stars appeared on herdress (which started with no stars). After several waves, Wandamultiplied the total number of stars then on her dress by thenumber of times she had waved her wand. This product cannot beA) 144 B) 256 C) 364 D) 676。

美国数学大联盟杯∙美国“数学大联盟杯赛”分为初赛，复赛，决赛三个层次。

初赛，复赛均在国内进行，采用美国大联盟杯赛原题（与美国同时同题）加上中国组委会命题的挑战题。

初赛采用在线考试方式，优秀者进入复赛，复赛为纸质试题。

复赛的优胜者进入决赛并，决赛在美国斯坦福大学举行，同时在那里参加为期5天的数学夏令营。

三年级的数学竞赛试题采用美国“数学大联盟杯赛”试题(一级)，加上组委会命题的挑战题。

竞赛时间为60分钟。

全部采用选择题或填空题(共40题)，总分200分。

其中40%的题目翻译成中文，其余60%为英文原题。

学生可以携带正规出版社出版的纸质简明英汉数学字典。

(禁止携带任何电子版的英汉字典、电子词典或计算器等。

)∙四年级的数学竞赛试题采用美国“数学大联盟杯赛”试题(二级)，加上组委会命题的挑战题。

竞赛时间为60分钟。

全部采用选择题或填空题(共40题)，总分200分。

其中30%的题目翻译成中文，其余70%为英文原题。

学生可以携带正规出版社出版的纸质简明英汉数学字典。

(禁止携带任何电子版的英汉字典、电子词典或计算器等。

)∙五年级的数学竞赛试题采用美国“数学大联盟杯赛”试题(三级)，加上组委会命题的挑战题。

竞赛时间为90分钟。

全部采用选择题或填空题(共50题)，总分250分。

其中20%的题目翻译成中文，其余80%为英文原题。

学生可以携带正规出版社出版的纸质简明英汉数学字典。

(禁止携带任何电子版的英汉字典、电子词典或计算器等。

)∙六年级、七年级(初一)的竞赛采用美国“数学大联盟杯赛”试题(四级)，加上组委会命题的挑战题。

竞赛时间为90分钟。

全部采用选择题或填空题(共50题)，总分250分。

所有题目英文命题。

学生可以携带正规出版社出版的纸质简明英汉数学字典。

(禁止携带任何电子版的英汉字典、电子词典或计算器等。

)∙初二、初三的竞赛采用美国“数学大联盟杯赛”试题(五级)，加上组委会命题的挑战题。

竞赛时间为120分钟。

全部采用选择题或填空题(共60题)，总分300分。

2022-2023年度美国Math League思维探索第一阶段活动(三年级)(答题时间：75分钟，总分：175分)学生诚信协议：答题期间，我确定没有就所涉及的问题或结论，与任何人、用任何方式交流或讨论，我确定我所填写的答案均为我个人独立完成的成果，否则愿接受本次成绩无效的处罚。

选择题：每小题5分，答对加5分，答错不扣分，共175分。

1.2–0+2–1+2–2+2–3=A)2B)3C)4D)52.Sandy the Snail ran6cm in an hour!At that rate,how many cm could she runin4hours?A)10B)12C)24D)303.2022+2023=4044+?A)0B)1C)2D)44.The names of how many months begin with a vowel?A)0B)1C)2D)35.Tyson eats only chicken2days a week,only sausages3days a week,and onlyhamburgers the rest of the week.Tyson eats hamburgers?days a week.A)1B)2C)4D)56.When?is divided by6,the remainder is4.A)20B)22C)24D)267.I began with20hats9years ago.For the first5years after that,each year I doubled the number of hats Ihad.For the next4years,each year I gave away half of my hats.How many hats do I have now?A)10B)20C)30D)408.(60+40+20)–(50+30+10)=A)10B)20C)30D)609.Turbo Turtles are toys that can run one-half of1km in2minutes.The average hourly speed of a TurboTurtle isA)15km/hr.B)20km/hr.C)30km/hr.D)60km/hr.10.The sum of the hundreds and ones digits of the product of12and34isA)9B)10C)11D)1211.How many different possible perimeters could a rectangle that has area100cm2and side-lengths that areall whole numbers have?A)4B)5C)6D)712.20+31+42=23+34+?A)36B)39C)45D)4813.Five days ago my birthday was exactly three weeks away.Today my birthday is?days away.A)16B)18C)25D)2614.Sophia Squirrel started with44acorns and found4more,then divided all of heracorns equally among her4friends.How many acorns did each friend get?A)4B)7C)11D)1215.If my motorcycle travels135km on9L of gas,how far can it travel on2L at that same rate?A)20km B)25km C)30km D)35km16.I have an odd number of nickels and an odd number of quarters.What could be the total value of all mynickels and quarters?A)$0.75B)$1.20C)$2.55D)$5.2517.Two train cars are placed end-to-end,and one car is twice as long as the other.If the total length is48m,the longer car has lengthA)16m B)20m C)28m D)32m18.200+200+200+200=40×?A)5B)10C)16D)2019.Franny Farmer has an empty bucket that can hold up to30oranges.Each morninghe puts5oranges in it,and each evening he eats3oranges.In how many dayswill he need a2nd bucket to hold his oranges?A)13B)14C)15D)1620.10×100×1000×10000=100000×1000000÷?A)10B)100C)1000D)1000021.Victor has100same-sized Rubik’s Cubes,and boxes that hold8Cubes each.How many boxes must hehave to hold all the Cubes?A)12B)13C)14D)1522.Stevie counted even numbers backwards,and the22nd number he counted was22.At what number didhe start counting?A)64B)66C)68D)7023.The product of two whole numbers,each of which is less than1000,can have at most?digits.A)5B)6C)7D)824.Rhonda the Racehorse runs70km in1hour.Sammy the Sloth runs1km in4hours.At these rates,Rhonda runs?km farther than Sammy in8hours.A)552B)556C)558D)55925.Jonah found the difference between a two-digit number and the number formed by reversing the digits inthe two-digit number.This difference could beA)72B)74C)76D)7826.A square and a rectangle have equal perimeters.If the length of a side of the square is6cm and thelength of one side of the rectangle is2cm,the length of the longer side of the rectangle is?cm.A)10B)12C)18D)2027.The time on Noelle’s digital clock was5:55PM.How many minutes later didNoelle next see all identical digits?A)71B)316C)376D)43628.Between which numbers listed do the greatest number of primes fall?A)20and30B)30and40C)40and50D)50and6029.If a line segment divides a certain polygon into a square and a triangle with the square and the trianglesharing a common side,the greatest number of sides this polygon could have isA)5B)6C)7D)830.When talking about a number,Marcia said,“It is an odd number,”and Jan said,“Both of the digits aredifferent.”If only one of them is telling the truth,what could the number be?A)20B)21C)22D)2331.It cost me$30to buy2balls and2bats.At the same unit prices,it cost mysister$65for5balls and4bats.The cost of1bat isA)$5B)$10C)$15D)$2032.What is the sum of all the positive divisors of18?A)20B)28C)30D)3933.The number of orangutans living in my tree increases by a constant numbereach year.If there are40orangutans now and there were24two years ago,how many orangutans will be in my tree in six years?A)64B)72C)88D)13634.The ratio of game stands to food stands at the beach boardwalk is currently3:1.There are80food stands.How many game stands must be converted to food stands to make the ratio1:1?A)40B)80C)120D)16035.The product of three whole numbers is36.What could not be the sum of the three?A)10B)11C)12D)13。

2017-2018年度美国“数学大联盟杯赛”(中国赛区)初赛(六年级)(初赛时间：2017年11月26日，考试时间90分钟，总分200分)学生诚信协议：考试期间，我确定没有就所涉及的问题或结论，与任何人、用任何方式交流或讨论， 我确定我所填写的答案均为我个人独立完成的成果，否则愿接受本次成绩无效的处罚。

请在装订线内签名表示你同意遵守以上规定。

考前注意事项：1. 本试卷是六年级试卷，请确保和你的参赛年级一致；2. 本试卷共4页(正反面都有试题)，请检查是否有空白页，页数是否齐全；3. 请确保你已经拿到以下材料：本试卷(共4页，正反面都有试题)、答题卡、答题卡使用说明、英文词汇手册、 草稿纸。

考试完毕，请务必将英文词汇手册带回家，上面有如何查询初赛成绩、 及如何参加复赛的说明。

其他材料均不能带走，请留在原地。

选择题：每小题5分，答对加5分，答错不扣分，共200分，答案请填涂在答题卡上。

1. Pick any integer greater than 1. Double it twice, then triple the result. The final outcomeis ? of your starting integer.A) 700%B) 1100%C) 1200%D) 1300%2. Barry listened to the radio for 3 hours and 36 minutes. Rounded to thenearest 10 minutes, for how many minutes was Barry listening? A) 210 B) 220 C) 330 D) 340 3. Divide 99 by 22 to get a quotient and remainder. Divide that remainder by that quotient, and the new remainder is A) 4 B) 3 C) 2 D) 14. A man had five pieces of chain, each made up of three links, figure below. He wanted to join the five pieces together to make a big chain of fifteen links and went to a blacksmith to see how much it would cost. “Well,” said the blacksmith, “I will charge you 50 cents for cutting a link and $1.00 for welding a link. Any bending that is required is free.” Given those prices, what is the smallest amount of money for which the job could be done? Note: In a chain, each link is connected to one or two other links. A) $4.50 B) $5.00 C) $5.50 D) $6.00 5. A bee sat on the head of a horse rider whose horse was trotting eastbound at a steady five miles per hour. Some distance ahead on the same path, another horse and rider were approaching westbound, also at five miles per hour. When the two horses were 20 miles apart, the bee left the first horse rider and flew toward the second horse at a rate of ten miles per hour. Upon reaching the second horse, the bee immediately turned around and flew back at the same rate to the first horse. If the bee kept up this performance until the two riders met, how far (in miles) did he travel from the moment he left the first horse rider?A) 10B) 20C) 30D) None of the above6. Which of the following is the sum of the prime factors of 2018?A) 11 B) 219 C) 1011 D) 20197. If the length of the longest side of a triangle is 18, which of the following could not be the length of its second-longest side? A) 9 B) 10 C) 12 D) 17 8. My final score in a competition is the average of my scores on 5 rounds. To get a final score of 88 after getting 84, 80, and 92 on the first 3 rounds, what must be my average score for the last 2 rounds? A) 88 B) 90 C) 92 D) 96 9. Mr. Rice had breakfast one day at a restaurant with Mr. Wheat. When it came time to pay the bill, it was found that Mr. Rice had as many one-dollar bills as Mr. Wheat had quarters. (Mr. Rice had one-dollar bills only, and Mr. Wheat had quarters only.) Rather than each man paying separately, Mr. Rice paid his share of the bill, $6, to Mr. Wheat. At that point, Mr. Wheat had four times as much money as Mr. Rice. How much money did Mr. Rice have at the beginning? A) $6 B) $8 C) $9 D) $12 10. Professor Peach teaches chemistry to clever kids. The ratio of freshmen to other students in his class is 3:8. The total number of students in Professor Peach’s class could be A) 42 B) 45 C) 56 D) 77 11. 440 ÷ 220 = A) 22B) 24C) 220D) 26012. Mr. Bogsworth once left a will which read:To Bob, twice as much as to Betty. To Brian, twice as much as to Bob. To Bill, twice as much as to Brian.If his estate was valued at $45000, how much money did Betty, one of his four heirs, receive? A) $1000 B) $2000 C) $3000 D) $6000 13. I paid $5 and got 5 quarters, 5 dimes, and 5 nickels in change. I spent A) $3.00 B) $3.25 C) $3.45 D) $3.75 14. One side of Todd ’s truck is a perfect rectangle with an area of 12 m 2. If its length is 3 times its width, then its perimeter is A) 8 m B) 12 m C) 16 m D) 20 m15. If a bird in the hand is worth two in the bush, and a bird in the bush is worth four in the sky, then 4 birds in the hand are worth ? birds in the sky.A) 1B) 4C) 16D) 3216. On each of the four shelves of my bookcase is a different prime number of books. Therecould be a total of ? books on my shelves.A) 15B) 21C) 22D) 24第1页，共4页 第2页，共4页Seven years ago I realized that my age would be tripled twelve years from then. How old am I now? A) 11 B) 13 C) 16 D) 18How many fractions with a numerator of 1 and a whole-number denominator are greater than 0.01 and less than 1? A) 98 B) 99 C) 100 D) 101If I write the letters R-E-P-E-A-T repeatedly, stopping when I have written exactly 100 letters, how many times do I write the letter E? A) 16 B) 18 C) 32 D) 34On my map, 1 cm represents 100 km. If a park shown on the map is a rectangle that is2.5 cm by 4 cm, the area of the actual park is ? km 2. A) 100 B) 1000 C) 10 000 D) 100 000Gloomy Gus’s Tu esday rain cloud shows up every Tuesday at 8:30 A.M.and every 50 minutes after that. Its last appearance on Tuesday is at ? P.M.A) 11:00 B) 11:10 C) 11:30 D) 11:50If my lucky number divided by its reciprocal is 100, then the square ofmy lucky number isA) 100 B) 10 C) 1D) 1100A boy and his sister were walking down the street one afternoon when they met a kind old man. When the old man asked them about the size of their family, the boy quicklyanswered. “I have as many brothers as I have sisters,” he proudly stated. Not to be left out, the girl added, “I have three times as many brothers as I have sisters.” Can you tell how many boys and girls in total there were in their family? A) 5 B) 6 C) 7 D) 8A farmer was asked how many pigs he had. “Well,” he said, “if I had just as m any more again, plus half as many more, plus another 1.5 times more, I would have three dozen.” How many pigs did he have?A) 6 B) 9 C) 12 D) 15 15% of 80 is 40% ofA) 30B) 55C) 105D) 210It took me 90 minutes to cycle 45 km to the beach. Later I got a ride from the beach tothe park at twice my cycling speed. If the ride to the park took 15 minutes, what distance did I travel from the beach to the park?A) 15 kmB) 30 kmC) 45 kmD) 135 kmTed, Rick, and Sam painted a wall together. Ted painted 80% more ofthe wall than Sam painted. Sam painted 40% less than Rick. Ted painted ? of the amount that Rick painted. A) 102% B) 108% C) 120% D) 140% The greatest integer power of 20 that is a divisor of 5050 isA) 2020B) 2025C) 2050D) 2012529. The ones digit of the sum of all even integers from 2 to 1492 is A) 2B) 4 C) 8 D) 030. The median of 12, 13, 14, 15, 16, and 17isA) 18 B) 223840 C) 514 D) 94031. The average of all positive even integers from 2 to 2018 is A) 1000 B) 1009 C) 1010 D) 1014 32. Pirate Percy has 300 coins in his chest. Of the Spanish coins,20% are gold. If 100 of the coins are gold but not Spanish and 70 of the coins are neither gold nor Spanish, how many Spanish gold coins are in Percy’s chest?A) 20 B) 26 C) 30 D) 3433. When I divided the population of my city by the number of streets in the city, I got a remainder of 18. If the exact quotient on my calculator was 123.06, how many streets are there in my city? A) 60 B) 120 C) 186 D) 30034. What is the greatest number of 3-by-7 rectangles that can be placed inside an 80-by-90 rectangle with no overlapping?A) 312B) 330C) 334D) 34235. How many four-digit whole numbers have four different even digitsand a ones digit greater than its thousands digit?A) 36B) 54C) 60D) 9036. Both arcs AB and AD are quarter circles of radius 5, figure on the right.Arc BCD is a semi-circle of radius 5. What is the area of the region ABCD ? A) 25 B) 10 + 5π C) 50 D) 50 + 5π 37. In the figure on the right, the side-length of the smaller square is 4. The four arcs are four semi-circles. Each side of square ABCD is tangent to one of the semi-circles. The area of ABCD is A) 32 B) 36 C) 48 D) 6438. A million is a large number, a “1” followed by 6 zeros. A googol is a large number, a “1” followed by one hundred zeros. Agoogo lplex is a large number, a “1” followed by a googol of zeros. A googolplexian is a large number, a “1” followed by a googolplex of zeros. A googolplexian isA) 1010 B) 1001010 C) 100101010 D) none of the above 39. If the total number of positive integral divisors of n is 12, what is the greatest possibletotal number of positive integral divisors of n 2? A) 23 B) 24 C) 33 D) 4540. Of all the isosceles triangles whose perimeter is 20 and whose side-lengths are integers, what is the length of the base of the triangle with the largest area? A) 2 B) 5 C) 6 D) 8第3页，共4页第4页，共4页。

2018-2019年度美国“数学大联盟杯赛”(中国赛区)初赛(五年级)(初赛时间：2018年11月14日,考试时间90分钟,总分200分)学生诚信协议：考试期间,我确定没有就所涉及的问题或结论,与任何人、用任何方式交流或讨论,我确定以下的答案均为我个人独立完成的成果,否则愿接受本次成绩无效的处罚。

如果您同意遵守以上协议请在装订线内签名选择题：每小题5分,答对加5分,答错不扣分,共200分,答案请填涂在答题卡上。

1. A 6 by 6 square has the same area as a 4 by ? rectangle.A) 3 B) 6 C) 8 D) 92.Every prime has exactly ? positive divisors.A) 1 B) 2 C) 3 D) 4 or more3.If I answered 34 out of 40 questions on my math test correctly, I answered ? % of thequestions correctly.A) 75 B) 80 C) 85 D) 904.120 ÷ 3 ÷ 4 × 12 =A) 1 B) 10 C) 12 D) 1205.10 × 20 × 30 × 40 = 24 ×?A) 1000 B) 10 000 C) 100 000 D) 1000 0006.One of my boxes contains 1 pencil and the others each contain 5 pencils. If there are 101pencils in my boxes, how many boxes do I have?A) 19 B) 20 C) 21 D) 227.An electrical company imports 2016 light bulbs. Unfortunately, 25%of those are damaged. How many light bulbs are not damaged?A) 25 B) 504 C) 1512 D) 20168.50 × (16 + 24) is the square ofA) -40 B) -4 C) 4 D) 809.Which of the following numbers has exactly 3 positive divisors?A) 49 B) 56 C) 69 D) 10010.Ten people stand in a line. Counting from the left, Jerry stands at the 5th position.Counting from the right, which position is he at?A) 4 B) 5 C) 6 D) 7 11.On a teamwork project, Jack contributed 2/7 of the total amount of work, Jill contributed1/4 of the work, Pat contributed 1/5 of the work, and Matt contributed the rest. Whocontributed the most toward this project?A) Jack B) Jill C) Pat D) Matt12.Which of the following numbers is a factor of 2016?A) 5 B) 11 C) 48 D) 9913.2 × 4 × 8 × 16 × 32 × 64 =A) 210B) 215C) 221D) 212014.On a game show, Al won four times as much as Bob, and Bob won four times as much asCy. If Al won $1536, how much did Al, Bob, and Cy win together?A) $96 B) $384 C) $1920 D) $201615.The sum of two composites cannot beA) odd B) even C) 11 D) 1716.If a and b are positive integers such that a/b = 5/7, then a + b isA) 12 B) 24 C) 36 D) not able to be determined17.What is the greatest odd factor of the number of hours in all the days of the year 2015?A) 3 B) 365 C) 1095 D) 328518.If the current month is February, what month will it be 1 199 999 months from now?A) January B) February C) March D) April19.Two angles are complementary. One of these angles is 36° less than the other. What is themeasure of the larger angle?A) 36°B) 54°C) 63°D) 72°20.(The square root of 16) + (the cube root of 64) + (the 4th root of 256) =A) 12 B) 24 C) 32 D) 6421.In ∆ABC, m∠A–m∠B = m∠B–m∠C. What is the degree measure of ∠B?A) 30 B) 60 C) 90 D) 12022.For every 3 math books I bought, I bought 2 biology books. I bought 55 books in all. Howmany of those are math books?A) 11 B) 22 C) 33 D) 4423.John wrote a number whose digits consists entirely of 1s. This number was a compositenumber. His number could contain exactly ? 1s.A) 17 B) 19 C) 29 D) 3224.Weird Town uses three types of currencies: Cons, Flegs, and Sels. If 3 Sels = 9 Cons and 2Cons = 4 Flegs, then 5 Sels = ? Flegs.A) 12 B) 24 C) 30 D) 36第1页,共4页25.If the length of a rectangular prism with volume V is doubled while the width and theheight are halved, the volume of the new prism will beA) 4V B) V/2 C) V D) 2V26.Rick and Roy each stands at different ends of a straight road that is 64 m long. They runtoward each other. Rick’s speed is 3 m/s and Roy’s speed is 5 m/s. They will meet in? seconds.A) 1 B) 2 C) 4 D) 827.If the area of a certain circle is 2016, its radius isA) sqrt(2016/π) B) sqrt(4032/π)C) 2016/πD) 1008/π28.In a toy shop, the cost of a Teddy Bear is 200% as much as that of a toy train. The cost ofa toy train is 6/5 the cost of a pack of the wooden blocks. The cost of a pack of woodenblocks is $50. What is the cost, in dollars, of the Teddy Bear?A) 60 B) 100 C) 120 D) 20029.In the sequence 2016, 225, 141, 66, 432, 99, 1458 …, each term after the first term is thesum of the cubes of the digits of the previous term. What is the 100th term of thissequence?A) 153 B) 351 C) 370 D) 37130.What is the sum of all the positive divisors of 210?A) 210 – 1 B) 211 – 1 C) 212 – 1 D) 213 – 131.It takes 4 hours for Mike and Lucy to finish a task. It takes Lucy and Jerry 5 hours tofinish the same task. And it takes 6 hours for Mike and Jerry to finish the same task. Lucy and Jerry first work on the task for 1 hour and 45 minutes. Then Mike takes over the task on his own. How many more hours does it take for Mike to finish the task?A) 3 B) 4 C) 5 D) 632.If you sell a cloth at its current price, you get $40 profit. The total profit you get selling 10clothes at 70% of its current price is equal to the total profit you get selling 20 clothes at $82 per cloth. What is the current price of a cloth?A) 80 B) 100 C) 120 D) 12533.There are 6 identical squares in the figure on the right. The side length of eachsquare is 1. Of all the triangles constructed by connecting three of the 18vertices in the figure, how many of them are triangles whose area is 2 andwhich has at least one vertical or horizontal side?A) 12 B) 16 C) 24 D) 2834.Pick up N numbers from 1 to 2015 inclusively, such that the sum of any three of the Nnumbers is divisible by 24. What is the maximum value of N?A) 83 B) 84 C) 168 D) 252 35.汤姆有一件花了64美金买来的衬衫,他打算以比原价高出25%的价格出售,他会卖出多少钱？A) $16 B) $32 C) $48 D) $8036.满足以下条件的最小整数是多少：“除以3余2,除以5余4,除以7余6。