Number Ninjas
Which number is a multiple of 6?
A. 14
B. 18
C. 22
D. 25
B
Explanation: 6x3=18.
What comes next? 6, 12, 18, 24, ___
A. 26
B. 28
C. 30
D. 36
C
Add 6 each time.
What is 7 × 8?
A. 48
B. 54
C. 56
D. 64
7 groups of 8 equal 56.
What is 48 ÷ 6?
A. 6
B. 7
C. 8
D. 9
6 × 8 = 48.
A rectangle is 8 units long and 3 units wide. What is its area?
A. 11 square units
B. 22 square units
C. 24 square units
D. 32 square units
Area = length × width = 8 × 3 = 24 square units.
Which number is a factor of 36?
A. 5
B. 7
C. 9
D. 10
9 × 4 = 36.
What is the rule? 3, 8, 13, 18, 23
A. Add 3
B. Add 5
C. Multiply by 3
D. Multiply by 5
B
Each term increases by 5.
What is 24 × 3?
A. 62
B. 72
C. 82
D. 92
B
(20 × 3) + (4 × 3) = 60 + 12 = 72.
What is 96 ÷ 3?
A. 23
B. 32
C. 33
D. 36
B
90 ÷ 3 = 30 and 6 ÷ 3 = 2.
A rectangle is 9 feet long and 4 feet wide. What is its perimeter?
A. 13 feet
B. 26 feet
C. 36 feet
D. 40 feet
B
Perimeter = 9 + 4 + 9 + 4 = 26 feet.
Which number is prime?
A. 21
B. 29
C. 33
D. 39
B
29 has exactly two factors: 1 and 29.
A machine multiplies each input by 4. What is the output for an input of 7?
A. 11
B. 24
C. 28
D. 32
C
7 × 4 = 28.
Which expression represents 6 × 42 using the distributive property?
A. (6 × 40) + (6 × 2)
B. (6 × 4) + (6 × 2)
C. (6 × 40) + 2
D. (6 + 40) × 2
A
42 = 40 + 2, so 6 × 42 = 240 + 12 = 252.
Which expression correctly decomposes 156 ÷ 3?
A. (150 ÷ 3) + (6 ÷ 3)
B. (15 ÷ 3) + (6 ÷ 3)
C. (150 ÷ 3) + (6 × 3)
D. (156 ÷ 3) + 3
A
156 = 150 + 6. Divide both parts by 3 to get 50 + 2 = 52.
A rectangle has an area of 48 square centimeters and a width of 6 centimeters. What is its length?
A. 6 cm
B. 7 cm
C. 8 cm
D. 9 cm
C
48 ÷ 6 = 8 centimeters.
Which list contains ONLY factors of 24?
A. 1, 2, 3, 6, 8, 24
B. 1, 2, 4, 5, 8, 24
C. 2, 3, 6, 7, 12, 24
D. 1, 3, 5, 6, 12, 24
A
Every number in A divides 24 evenly. The complete factor list also includes 4 and 12.
A pattern begins at 4 and adds 3 each time. Which statement about its terms is true?
A. All terms are even.
B. All terms are odd.
C. Odd and even terms alternate.
D. Every term is a multiple of 3.
C
The pattern is 4, 7, 10, 13, 16 ... Every other term is an odd number.
A student solves 8 × 35 as (8 × 3) + (8 × 5) = 64. What is the error?
A. The student should have added 8 and 35.
B. The student forgot to multiply by 8.
C. The student treated 30 as 3.
D. The student should have divided by 8.
C
35 decomposes into 30 + 5, not 3 + 5. The correct product is 280.
A student claims 248 ÷ 4 = 52. Which statement identifies the mistake?
A. The quotient should be 42.
B. The quotient should be 62.
C. The divisor should be 8.
D. The student should multiply 248 by 4.
B
240 ÷ 4 = 60 and 8 ÷ 4 = 2, so the quotient is 62.
A backpack costs 4 times as much as a pencil case. The backpack costs $72. Which equation finds the pencil case price?
A. 72 × 4 = □
B. □ + 4 = 72
C. □ × 4 = 72
D. □ − 4 = 72
C
The unknown price multiplied by 4 equals $72, so the pencil case costs $18.
Mia says, 'All odd numbers are prime.' Which statement proves Mia is incorrect?
A. 2 is a prime number.
B. 9 is odd and has three factors.
C. 7 is odd and prime.
D. 15 is an even number.
B
9 is odd, but its factors are 1, 3, and 9, so it is composite.
A tricycle has 3 wheels. A table shows 1 tricycle = 3 wheels, 2 = 6, and 3 = 9. How many wheels are on 12 tricycles?
A. 15
B. 24
C. 36
D. 48
C
The rule is multiply the number of tricycles by 3. 12 × 3 = 36.
Which equation correctly uses the distributive property to solve 27 × 14?
A. (20 × 10) + (7 × 4)
B. (27 × 10) + (27 × 4)
C. (27 × 1) + (27 × 4)
D. (20 × 14) + 7
B
14 = 10 + 4. The partial products are 270 and 108, totaling 378.
A school has 936 pencils. The pencils are divided equally among 6 classrooms. How many pencils does each classroom receive?
A. 146
B. 154
C. 156
D. 166
C
936 ÷ 6 = 156. Verify: 156 × 6 = 936.
Two rectangles each have an area of 36 square units. Rectangle A measures 4 by 9 units. Rectangle B measures 3 by 12 units. Which statement is true?
A. Both have a perimeter of 26 units.
B. Rectangle A has a greater perimeter.
C. Rectangle B has a greater perimeter.
D. Both have a perimeter of 36 units.
C
A has perimeter 26 units; B has perimeter 30 units. Equal areas do not require equal perimeters.