54. 200 - (80 - 35) * 2; 200 - 80 - 35 * 2; 446 - (46 + 4 * 8); 540 - (90 - 30 : 6)

Решение:

1. $$200 - (80 - 35) \cdot 2 = 200 - 45 \cdot 2 = 200 - 90 = 110$$
2. $$200 - 80 - 35 \cdot 2 = 200 - 80 - 70 = 120 - 70 = 50$$
3. $$446 - (46 + 4 \cdot 8) = 446 - (46 + 32) = 446 - 78 = 368$$
4. $$540 - (90 - 30 : 6) = 540 - (90 - 5) = 540 - 85 = 455$$