10 * (7 * 9 - 7 * 8) - 5 * 8 + 8 * 5 = 70
1) 7 * 9 = 63
2) 7 * 8 = 56
3) 63 - 56 = 7
4) 10 * 7 = 70
5) 5 * 8 = 40
6) 8 * 5 = 40
7) 70 - 40 = 30
8) 30 + 40 = 70
