Question

how many three-digit numbers less than 700 can be made using the digits 9, 7, 5, and 3 at most once? assume digits cannot be reused.

Answer 1

There are 24 three-digit numbers less than 700 that can be made using the digits 9, 7, 5, and 3 at most once. They are:

395, 379, 357, 593, 597, 537, 573, 935, 937, 957, 975, 375, 735, 753, 793, 359, 539, 579, 953, 973, 357, 537, 573