Math League 5th 2021真题
1. 9000 + 900 + 90 + 9 = 10000 - ?
A) 1 B) 4 C) 1000 D) 1111
2. If 30 of my 6-dozen pencils were sharp, how
many of my pencils were not sharp?
A) 18 B) 24 C) 36 D) 42
3. (2021 × 1) + (2020 × 0) = 2021 + ?
A) 0 B) 1 C) 2020 D) 2021
4. The number of cats I have is 5 × 5 more than 5 cats. I have ? cats.
A) 15 B) 25 C) 30 D) 125
5. If every digit of my secret code is a different prime number, my secret code has at most ? digits.
A) 4 B) 5 C) 6 D) 7
6. How many digits does the product of ten 100s have?
A) 3 B) 4 C) 20 D) 21
7. 8 + 8 × 8 + 8 = (8 + 8) × ?
A) 5 B) 6 C) 7 D) 8
8. A herd that can be divided into 12 groups of 4 animals
can also be divided into ? groups of 3 animals.
A) 9 B) 11 C) 16 D) 18
9. What is the smallest difference between two whole numbers whose product is 123?
A) 38 B) 41 C) 44 D) 122
10. The perimeter of a square with odd side-lengths could be
A) 6 B) 8 C) 10 D)12
11. The time 1 hour and 1 minute before midnight is
A) 1:01 AM B) 10:59 PM C) 11:01 PM D) 11:59 PM
12. Which of the following is the product of two prime numbers?
A) 104 B) 114 C) 124 D) 134
13. Fido fetches 3 out of every 54 balls Flo throws.
At this rate, how many balls must Flo throw to
be sure that Fido fetches 54 balls?
A) 18 B) 162 C) 972 D) 2916
14. How many 2-digit multiples of 15 are also multiples of 6?
A) 0 B) 3 C) 4 D) 5
15. Al chews half of his gum each day. If Al chewed 6 sticks of gum today, how many sticks of gum did he chew 4 days ago?
A) 30 B) 48 C) 96 D) 192
16. How many whole numbers are factors of 3 × 5 × 7?
A) 3 B) 5 C) 7 D) 8
17. Ava bought more than 1 new book for $8 each, and more than 1 used book for $3 each. The total cost of her books could be
A) $23 B) $24 C) $25 D) $26
18. I started writing all the multiples of 2 in increasing order, starting with 2. What was the 45th digit I wrote?
A) 3 B) 5 C) 7 D) 9
19. What is the sum of the digits of the product of the greatest 3-digit whole number and the smallest 4-digit whole number?
A) 27 B) 28 C) 36 D) 37
20. A square with perimeter 24 is cut into two identical rectangles. The perimeter of one of these two rectangles is
A) 9 B) 12 C) 18 D) 24
21. Kai makes 3 times as many clocks a day working with
a friend as she does working alone. Kai and her friend
make 60 clocks a day when they work together. How many
clocks can Kai make in 5 days when she works alone?
A) 20 B) 36 C) 100 D) 180
22. My house number does not have 2, 3, or 5 as a factor. Which of the following could be my house number?
A) 66 B) 77 C) 88 D) 99
23. The average of 5 different whole numbers greater than 0 is 40. What is the greatest possible value of one of the whole numbers?
A) 42 B) 190 C) 196 D) 200
24. Bob bought 36 cups at a cost of 4 cups for $5. He will resell the cups for $2 each. How many cups must Bob sell to earn at least what he paid for all 36 cups?
A) 3 B) 9 C) 22 D) 23
25. The positive multiples of a whole number were listed from least to greatest. If the 3rd multiple was 42, the 5th multiple was
A) 28 B) 56 C) 70 D) 126
26. At 65 Flavors Ice Cream Shop, every 65th
customer wins free ice cream. If the 50th
winner was 25 customers before me,
what number customer am I?
A) 90 B) 3225 C) 3250 D) 3275
27. Cog counted down from 2021 by subtracting 7 repeatedly. How many positive multiples of 3 did Cog count?
A) 94 B) 95 C) 96 D) 97
28. There are 8 rows of chairs, with 18 chairs in each row. If we keep all the chairs, what is the smallest number of chairs we must move so that the number of rows equals the number of chairs in each row?
A) 8 B) 18 C) 32 D) 48
29. Sal added two consecutive integers greater than 10.
Adding 2 to the greater integer would increase the tens
digit of their sum. What is the smallest possible value of
the smaller integer?
A) 11 B) 14 C) 44 D) 98
30. The product of 5 different primes can be written as the product of at most ? different non-prime whole numbers.
A) 2 B) 3 C) 4 D) 5
