7 8 9 10四个数字加减乘除如何等于等于24呢?

给你一个网址,类似的问题都可解决：
1:8 - (7 - 9) × 8
2:8 - ((7 - 9) × 8)
3:8 - (8 × (7 - 9))
4:8 - 8 ×(7 - 9)
5:8 + (8 × (9 - 7))
6:8 + 8 ×(9 - 7)
7:8 + (9 - 7) × 8
8:8 + ((9 - 7) × 8)
9:(8 × (9 - 7)) + 8
10:8 × (9 - 7) + 8
11:(9 - 7) × 8 + 8
12:((9 - 7) × 8) + 8