SDN Members don't see this ad. (About Ads) Hey boys and girls. I've recently been getting really nervous about the probability portion of the math section. I understand easy probability like what are the chances of rolling a 4 on a die consecutively....but when do we exactly do the following: 1. Permutations like: 5! or some things like (5!)/(2!)(3!) 2. When do we multiply probabilities together. Like if there's 4 boys how many ways can we put them in order. Is it 4x4? 3. There are also random permutation equations that confuse me a lot So the general question is...are there easy ways to remember certain probability formulas? Cheers!