Examples. Start from the smallest prime and work your way. Keep using the smallest prime until it doesn't work anymore. If you get a decimal number, try a bigger prime. Keep going until you are dividing a prime by a prime which leaves a 1. (Primes are 2, 3, 5, 7, 11, 13, 17...)

Number to be factor: 330 Factorization tree: 2 divides into 330 leaving 165

3 divides into 165 leaving 55

5 divides into 55 leaving 11

11 divides into 11 leaving 1

STOP WHEN YOU GET TO 1

Number to be factor: 500 Factorization tree: 2 divides into 500 leaving 250

2 divides into 250 leaving 125

5 divides into 125 leaving 25

5 divides into 25 leaving 5

5 divides into 5 leaving 1

STOP WHEN YOU GET TO 1