Posted by mathrocks on Monday, September 14, 2009 at 10:37am.
hello My question is that how can we express 315 in prime factor?

math  bobpursley, Monday, September 14, 2009 at 10:41am
315 is first divisible by 5. I assume you know the divisibility rules.
61*5
Next, 61. Isn't that prime?
http://www.icteachers.co.uk/children/sats/primes.htm#1