Practice Composite Numbers in Math

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

Integers greater than 1 that can be expressed as a product of two smaller positive integers; they are the opposite of primes.

Numbers that can be built by multiplying smaller numbers together.

Showing a random 20 of 50 problems.

Example 1

medium
List all composite numbers between 50 and 60, with one factor pair each.

Example 2

easy
Determine whether 91 is prime or composite. If composite, find a factor pair.

Example 3

easy
Is 21 composite? If yes, give a factor pair other than 1×21.

Example 4

challenge
For n≥4, prove that n4+4 is composite for every integer n≥2.

Example 5

medium
Which composite numbers in {4,6,8,9,10} are odd?

Example 6

easy
Is 1 prime, composite, or neither?

Example 7

easy
True or false: every even number greater than 2 is composite.

Example 8

easy
Is 1 composite? Is 4 composite? Is 2 composite? Explain each briefly.

Example 9

hard
Determine whether 221 is prime or composite.

Example 10

easy
Is 25 composite?

Example 11

easy
Is 9 a composite number?

Example 12

medium
Is 143 prime or composite? Justify with a factorization if composite.

Example 13

medium
List all composite numbers between 1 and 10.

Example 14

challenge
Prove that the product of two consecutive integers greater than 1 is composite.

Example 15

easy
Is 49 prime or composite? Show a factorization if composite.

Example 16

medium
True or false: 0 is composite.

Example 17

medium
List all composite numbers between 20 and 35, and for each, give one non-trivial factor pair.

Example 18

easy
Name the smallest composite number.

Example 19

medium
Is 51 prime or composite? Test divisibility.

Example 20

easy
Give two different composite numbers between 30 and 40.