One example.
12*8+3+7-6 = 100
The key is finding sets of 10s
3! = 6.
4*3*2 = 24 of them.
5! / 4 - 2 * 3
total 6 they are 3412,4312,1324,3124,1432,4132
None.
5*4+3+2
3! = 6.
4*3*2 = 24 of them.
5! / 4 - 2 * 3
total 6 they are 3412,4312,1324,3124,1432,4132
8
(4+5-6)x8=24
If you want 4-digit numbers, there are 24 of them.
None.
-1230
One possible way to make 2000 using numbers between 1 and 9 once is: 9^3 − 8 × 7 − 6 × 5 × 4 − 3 × 2.
-9