I found this really useful article that describes using a flowchart how to attack any “counting” problem.
http://www.mansw.nsw.edu.au/members/reflections/vol21no1_larkin.htm
Remember:
Arranging – use a permutation (order is important in arrangements)
Choosing – use a combination (the order doesn’t matter, just whether something was chosen.
AND – multiply
OR – add – mutually exclusive
MrB's Blog 
And where do using a factorial tie into this?
What i mean is when do you use a facorial?
Hi Brady,
You use a factorial as a means of simplifying 5 * 4 * 3 * 2 * 1 = 5!
An example of this would be how many ways can I arrange 5 different coloured balls
Hope that helps
Hey Brady,
Did you get onto my blog at school? I didn’t think it would work?
Cheers
Mr B