Using the digits 1, 2, 3, 4, 5, how many even three-digit numbers less than 500 can be formed if each digit can be used at most once?
_ _ _
last digit 2 options (2, 4)
first digit 3 options (4, 3, 2, 1, but not 2 or 4), can't be 5 since that would be larger than 500. Minus 1 from the last digit.
middle digit 3 options. can't be first/last digit.
2*3*3 = 18
=^._.^=
