Select 1 unique numbers from 20 to 1
Total possible combinations (ways)
If order does not matter (e.g. most lottery numbers): -18
If order matters (e.g. pick3 numbers, permutations, lock combinations, pin-codes): -18
If order does not matter (e.g. most lottery numbers): -18
If order matters (e.g. pick3 numbers, permutations, lock combinations, pin-codes): -18