Select 2 unique numbers from 18 to 40
Total possible combinations (ways)
If order does not matter (e.g. most lottery numbers): 253
If order matters (e.g. pick3 numbers, permutations, lock combinations, pin-codes): 506
If order does not matter (e.g. most lottery numbers): 253
If order matters (e.g. pick3 numbers, permutations, lock combinations, pin-codes): 506