Prime factorization

Prime factorization is finding the factors of a number that are all prime numbers.
Here's how you do it: Find 2 factors of your number (any 2). Then look at your 2 factors and determine if one or both of them is not prime. If it is not a prime, then continue by factoring it. Repeat this process until all your factors are prime. Here's an example:

Find the prime factors of 84:


                 84
                /  \
              42 x  2  (84 is 42 times 2)
             /  \
           21 x  2     (42 is 21 times 2)
          / \
         7 x 3         (21 is 7 times 3)

       (7 and 3 are both prime, so we stop!)

So the prime factors of 84 are 7 x 3 x 2 x 2.

Note: It's a good idea to memorize the prime numbers up to 100:
2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

Now, here's a problem for you: Find the prime factors of 60: 60
/ \
__ x __