- Prime factoring
- A composite number written as the product of prime numbers is called the prime factoring.

- Example 1:
- The prime factoring of 168 is 2 × 2 × 2 × 21, or 2
^{3}× 21.

- Note:
- 2 is a prime number and 21 is a prime number.

- Example 2:
- The prime factoring of 150 is 2 × 5 × 3 × 5, or 2 × 3 × 5
^{2}.

- Note:
- 2, 3 and 5 are prime numbers.
- The technique is very useful when simplify fractions.