| Выражение | Решение | Ответ |
| \( 81 - 18 - 70 \) | \( 81 - 18 = 63 \) \( 63 - 70 = -7 \) | -7 |
| \( 63 - 21 + 48 \) | \( 63 - 21 = 42 \) \( 42 + 48 = 90 \) | 90 |
| \( 28 + 31 - 34 \) | \( 28 + 31 = 59 \) \( 59 - 34 = 25 \) | 25 |
| \( 54 - 37 + 68 \) | \( 54 - 37 = 17 \) \( 17 + 68 = 85 \) | 85 |
| \( 90 - 2 \cdot 6 \) | \( 2 \cdot 6 = 12 \) \( 90 - 12 = 78 \) | 78 |
| \( 3 \cdot 3 + 89 \) | \( 3 \cdot 3 = 9 \) \( 9 + 89 = 98 \) | 98 |
| \( 71 - 21 : 3 \) | \( 21 : 3 = 7 \) \( 71 - 7 = 64 \) | 64 |
| \( 9 : 3 \cdot 6 \) | \( 9 : 3 = 3 \) \( 3 \cdot 6 = 18 \) | 18 |
Ответ: -7, 90, 25, 85, 78, 98, 64, 18.