4th Grade Factors, Multiples, Prime and Composite Quiz: 10 Questions with Explanations

A 8B 5C 9D 7

36 divided by 9 is 4 with no remainder, so 9 is a factor. 36 divided by 8 is 4 with a remainder of 4.

A 1, 3, 5B 1, 3, 5, 15C 3, 5, 15D 1, 5, 15

The pairs are \(1 \times 15\) and \(3 \times 5\). Leaving out 1 or 15 is a common mistake.

A 39B 49C 51D 37

37 has only the factors 1 and 37. 39 = \(3 \times 13,\) 49 = \(7 \times 7\) and 51 = \(3 \times 17\) are composite.

A 63B 54C 65D 72

\(7 \times 9\) = 63. The numbers 54, 65 and 72 fall between multiples of 7.

A 8B 6C 3D 4

The array has 24 tiles. Factor pairs: \(1 \times 24,\) \(2 \times 12,\) \(3 \times 8,\) \(4 \times 6\). That is 4 pairs. Eight is the number of factors, not pairs.

A 36B 40C 42D 38

Each jump adds 8, so the next number is 32 + 8 = 40.

A 3,780B 3,785C 3,782D 3,781

A number ending in 0 is divisible by 2, 5 and 10. 3,785 ends in 5 (not even) and 3,782 ends in 2 (not a multiple of 5).

A 2 is the only even prime numberB 1 is a prime numberC All odd numbers are primeD Every composite number is even

2 has exactly two factors. Odd numbers like 9 and 15 are composite, and 1 has only one factor.

A 3B 9C 6D 27

There are 27 tiles. 27 divided by 6 is 4 with a remainder of 3, so 6 is not a factor.

A 52B 56C 60D 66

56 = \(8 \times 7\). The others leave pencils over: 52 leaves 4, 60 leaves 4, 66 leaves 2.