"Prime Factorization" is finding which prime numbers multiply together to make the original number.
∴ 8 = 2 * 2 * 2
And 16 = 2 * 2 * 2 * 2
∴ 8 + 16 = 2 * 2 * 2 + 2 * 2 * 2 * 2 ⇒⇒⇒ taking ( 2 * 2 * 2) as a common
∴ 8 + 16 = (2 * 2 * 2) ( 1 + 2 )
= 2 * 2 * 2 * 3
= 24