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 5050 and 6060, with one factor pair each.

Example 2

easy
Determine whether 9191 is prime or composite. If composite, find a factor pair.

Example 3

easy
Is 2121 composite? If yes, give a factor pair other than 1ร—211 \times 21.

Example 4

challenge
For nโ‰ฅ4n \ge 4, prove that n4+4n^4 + 4 is composite for every integer nโ‰ฅ2n \ge 2.

Example 5

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

Example 6

easy
Is 11 prime, composite, or neither?

Example 7

easy
True or false: every even number greater than 22 is composite.

Example 8

easy
Is 11 composite? Is 44 composite? Is 22 composite? Explain each briefly.

Example 9

hard
Determine whether 221221 is prime or composite.

Example 10

easy
Is 2525 composite?

Example 11

easy
Is 99 a composite number?

Example 12

medium
Is 143143 prime or composite? Justify with a factorization if composite.

Example 13

medium
List all composite numbers between 11 and 1010.

Example 14

challenge
Prove that the product of two consecutive integers greater than 11 is composite.

Example 15

easy
Is 4949 prime or composite? Show a factorization if composite.

Example 16

medium
True or false: 00 is composite.

Example 17

medium
List all composite numbers between 2020 and 3535, and for each, give one non-trivial factor pair.

Example 18

easy
Name the smallest composite number.

Example 19

medium
Is 5151 prime or composite? Test divisibility.

Example 20

easy
Give two different composite numbers between 3030 and 4040.