7+7+5+5
24
24 of them.
27
24
24 different numbers.
All numbers have factors. Some factors have one digit. The factors of 24 are 1, 2, 3, 4, 6, 8, 12, 24 The single digit factors of 24 are 1, 2, 3, 4, 6 and 8.
24 if you don't repeat any numbers.24
24
24 of them.
27
24
24 different numbers.
24
10, 24, 48, 80, 82
27
24 = 4*3*2*1
If you want 4-digit numbers, there are 24 of them.