Question 242034
<pre>
315 can be divided by 3


  105
 ----
3)315
  3
  --
   15 
   15
   --
    0

So 315 = 3*105

105 can be divided by 3:

   35
 ----
3)105
   9
  --
   15 
   15
   --
    0

So 315 = 3*3*35

35 can be divided by 5

   7
 --- 
5)35
  35
  --
   0

So 315 = 3*3*5*7

Those are all prime.  But we can write 3*3 as 3<sup>2</sup>

So 315 = 3<sup>2</sup>*5*7

So that's the prime factorization of 315.

Edwin</pre>