(6 x 13) - (6 x 9) = 78 - 54 = 24
3! = 6.
4*3*2 = 24 of them.
8
only using the numbers once
None.
If you want 4-digit numbers, there are 24 of them.
998,000
-9
2,5,13,647,809
1+2+3+4+5+6+7+8+9 = 45
(7 + 5 - 9) x 8 = 24
There is only one combination. In a combination the order of the numbers does not matter so the only combination is 0123456789. This is the same as 1326458097