Counting possibilities and arrangements
Product of numbers from 1 to n
Computing n!/(n-k)!
Cancellation in (n+k)!/n!
Find n where n! = X
Choosing k from n without order
P(n) = n! arrangements
n!/(k1! × k2!)
V(n,k) = n!/(n-k)!
V'(n,k) = n^k
All permutations visually
Structure of binomial coefficients