A factor is a natural number that exactly divides a given natural number.
Example 1: 6 is a factor of 12 [since 12 ÷ 6 = 2 (with a remainder of 0)].
Example 2: 12 is a factor of 12 [since 12 ÷ 12 = 1 (with a remainder of 0)].
Example 3: 8 is NOT a factor of 12 [since 12 ÷ 8 = 1 with a remainder of 4].