Calculer :

1. \( = 8 \times 5 - 3 \times 4 - 7 + 2 \)
2. \( = 2 \times (8 - 4) - 5 + 7 \times 3 \)
3. \( = 65 - (18 + 3 \times 9) + 7 \times 3 \)
4. \( = 2 \times (3 \times 5 - 1) - 5 \times (1 + 1 \times 3) \)