2021年大联盟(Math League)国际夏季四年级数学挑战活动二练习（含答案）

这是一份2021年大联盟(Math League)国际夏季四年级数学挑战活动二练习（含答案），共17页。试卷主要包含了 + = 2021 +?等内容，欢迎下载使用。

1. 8000 + 800 + 80 + 8 = 9000 –?
2
12
C) 112
D) 1112
Answer: C
2. If 30 f my 5-dzen pencils were sharp, hw many f my pencils were nt sharp?
10
20
30
50 Answer: C
3. (2021 × 1) + (2020 × 0) = 2021 +?
0
1
C) 2020
D) 2021
Answer: A
The number f dgs I have is 6 × 5 mre than 6 dgs. I have ? dgs.
15
24
36
66 Answer: C
If every digit f my secret cde is a different prime number, my secret cde has at mst ? digits.
4
5
6
7 Answer: A
Hw many digits des the prduct f ten 100s have?
3
4
20
21 Answer: D
I am reading a 300-page bk in 10 hurs, at a cnstant rate. Hw many pages have I read in the past 10 minutes?
5
10
15
30 Answer: A
A herd that can be divided int 16 grups f 4 animals can als be divided int
? grups f 8 animals.
6
8
12
16 Answer: B
What is the smallest difference between tw whle numbers whse prduct is 253?
2
11
12
D) 252
Answer: C
The perimeter f a square with dd side-lengths culd be
6
8
10
12 Answer: D
The time 2 hurs and 2 minutes befre midnight is
A) 2:02 AM
B) 10:58 PM
C) 9:58 PM
D) 11:58 PM
Answer: C
Which f the fllwing is the prduct f tw prime numbers? A) 100
B) 112
C) 120
D) 142
Answer: D
Fid fetches 3 ut f every 54 balls Fl thrws. At this rate, hw many balls must Fl thrw t be sure that Fid fetches 54 balls?
A) 18
B) 162
C) 972
D) 2916
Answer: C
Hw many 2-digit multiples f 15 are als multiples f 2?
0
3
4
5 Answer: B
Al chews half f his gum each day. If Al chews 6 sticks f gum tday, hw many
sticks f gum did he chew 4 days ag?
30
48
96
D) 192
Answer: C
Hw many whle numbers are factrs f 2 × 4 × 6?
5
6
8
10 Answer: D
Ava bught mre than 1 new bk fr $6 each, and mre than 1 used bk fr $5 each. The ttal cst f her bks culd be
A) $22
B) $23
C) $24
D) $25 Answer: A
I started writing all the multiples f 2 in increasing rder, starting with 2. What was the 45th digit I wrte?
3
5
7
9
Answer: B
What is the sum f the digits f the greatest 3-digit whle number and the digits f the smallest 4-digit whle number?
27
28
36
37 Answer: B
A square with perimeter 16 is cut int tw identical rectangles. The perimeter f ne f these tw rectangles is
8
12
16
24 Answer: B
Kai makes 4 times as many clcks a day wrking with a friend as she des wrking alne. Kai and her friend make 60 clcks a day when they wrk tgether. Hw many clcks can Kai make in 5 days when she wrks alne?
60
75
C) 100
D) 180
Answer: B
My huse number des nt have 2, 3, r 5 as a factr. Which f the fllwing culd be my huse number?
44
55
66
77 Answer: D
The average f 5 different whle numbers greater than 0 is 20. What is the greatest pssible value f ne f the whle numbers?
42
90
96
D) 100
Answer: B
Bb bught 36 cups at a cst f 4 cups fr $5. He will resell the cups fr $2 each. Hw many cups must Bb sell t earn at least what he paid fr all 36 cups?
3
9
22
23 Answer: D
The psitive multiples f a whle number were listed frm least t greatest. If the 3rd multiple was 39, the 5th multiple was
13
42
65
D) 117
Answer: C
At 65 Flavrs Ice Cream shp, every 65th custmer wins free ice cream. If the 50th winner was 25 custmers befre me, what number custmer am I?
A) 90
B) 3225
C) 3250
D) 3275
Answer: D
Cg cunted dwn frm 2021 by subtracting 7 repeatedly. Hw many psitive multiples f 3 did Cg cunt?
94
95
96
97 Answer: C
There are 8 rws f chairs, with 18 chairs in each rw. If we keep all the chairs, what is the smallest number f chairs we must mve s that the number f rws equals the number f chairs in each rw?
8
18
32
48 Answer: D
Sal added tw cnsecutive integers greater than 10. Adding 2 t the greater integer wuld increase the tens digit f their sum. What is the smallest pssible value f the smaller integer?
11
14
44
98 Answer: B
The prduct f 5 different primes can be written as the prduct f at mst
? different nn-prime whle numbers.
2
3
4
5 Answer: B
31. The average f 2018, 2020, 2021, 2022, and 2024 is
A) 5
B) 2019
C) 2021
D) 2022
Answer: C
The difference between any tw dd multiples f 3 is always
even
dd
3
6 Answer: A
What is the prbability that, in its spelling, a randmly chsen day f the week uses the letter “s” r “S”?
2 7
3 7
5 7
6 7
Answer: C
60 × 60 secnds =
36 minutes
600 minutes
6 hurs
1 hur Answer: D
Starting with January, number the mnths frm 1 t 12. Hw many f the dd-numbered mnths have an dd number f days?
1
2
3
4 Answer: D
Five years ag, Al was as ld as Bb is nw. In hw many years frm nw will Bb be as ld as Al is nw?
5
10
15
20 Answer: A
When Bucky gave me 8 cins wrth 25¢ t help him build a dam, he gave me exactly
1 nickel
2 dimes
3 nickels
5 pennies Answer: D
A rectangle has area 48 and integral sides. Its perimeter cannt be
38
42
52
98 Answer: B
The sum f 10 different whle numbers can be ? , but never less.
11
45
55
66 Answer: B
The perimeter f a triangle is 36cm. Its lngest side culd be
11 cm
17 cm
18 cm
19 cm Answer: B
I said “n stne shall g unturned” in my search fr different whle-number factrs f 36. Just hw many such factrs are there?
6
8
9
18 Answer: C
Pints A, B, C, and D lie n a line, but nt in that rder. If AB = 9, BC = 4, and CD = 2, the least pssible value f AD is
2
3
4
7 Answer: B
If the symbl hh:mm:ss means hurs:minutes:secnds, hw much time passes frm 5:55:55 P.M. until midnight?
A) 6:04:05
B) 6:05:05
C) 7:04:05
D) 7:05:05
Answer: A
Multiply the largest 2-digit prime by the smallest 3-digit prime. A) 1111
B) 9191
C) 9797
D) 9991
Answer: C
If a 卐 b means a × ( a – b) , what is the value f 4 卐 3?
-4
4
12
D) -12
Answer: B
6 quarters + 2 dimes = 20 pennies + ? nickels.
25
30
33
35 Answer: B
Huck is twice as ld as Becky and 2 years lder than Tm. If Becky is 13, hw ld is Tm?
14
20
22
24 Answer: D
The difference between tw primes, each greater than 100, is always
even
dd
cmpsite
prime Answer: A
Hw many different psitive primes are factrs f 2021?
2
3
4
5 Answer: A
If the sum f 4 cnsecutive dd numbers is 4 mre than the sum f 4 cnsecutive even numbers, then the least f the dd numbers is ? mre than the least f the even numbers.
1
2
3
4 Answer: A
The largest 4-digit integral multiple f 9 equals the largest 4-digit integral multiple f all f the fllwing except
3
11
17
D) 101
Answer: C
(the least psitive integer) – (the largest negative integer) =
2
1
0
-1 Answer: A
The greatest cmmn factr f 2 × 4 × 6 × 8 × 10 and 1 × 2 × 3 × 4 × 5 is
2
4
8
D) 120
Answer: D
What mnth will it be 1000 days after February 14?
Octber
Nvember
December
January Answer: B
Each side f a triangle has a different psitive integer as its length. What is the least pssible perimeter f this triangle?
3
6
9
12 Answer: C
If tday is Tuesday, what day will it be in 2022 days?
Mnday
Wednesday
Thursday
Saturday Answer: A
The sum f tw angles in an equilateral triangle is ? . A) 180
B) 120
90
60 Answer: B
What is the remainder when the prduct f all the prime numbers between 1 and 100 is divided by 4?
3
2
1
0 Answer: B
Each mnth, Dad gives me $1 n the 1st day, $2 n the 2nd day, $3 n the 3rd day,
and, in general, $n n the nth day f the mnth. During 1992, Dad gave me a ttal f ? .
A) $5395
B) $5738
C) $5767
D) $5797
Answer: C
60. If 10 + 20 + 30 + ... + 990 + 1000 = 50500, then what is the value f (10 – 1) +
(20 – 2) + (30 – 3) + ... + (990 – 99) + (1000 – 100)?
A) 40400
B) 45000
C) 45450
D) 50000
Answer: C