I keep forgetting some of the functions in excel and it is embarrassing to search for the same things every time.
PERMUT(n, r) = nPr = n! / (n - r)!
COMBIN(n, r) = nCr = n!/((n-r)!r!)
FACT(n) = n! = 1*2*3*...*n
BINOMDIST(s, n, p, cumul) Probability that there will be exactly s successes in n trials, each trial having a success probability of p (cumul = FALSE). If cumul is true it returns the probability that there will be at most s successes in n trials.