the number is even, so it is divisible by two. it is also divisible by 5. so start dividing it by prime numbers as much as possible. eventually you will see the number as a product of primes. if a prime repeats itself in the product, just rewrite it as that prime raised to the appropriate power.

example, lets do what i said for 360

divide by 2 we get: 180

divide by 2 again we get: 90

divide by 2 again, we get: 45

two can't go into this, what other prime i know can? let's try 5

divide by 5 we get: 9

aha, now divide by 3 to get 3 and again by 3 to get 1, and we're done.

so, 360 = 2 x 2 x 2 x 5 x 3 x 3 =