1. 5 + 8 × 3 - 2 = ? 2. 12 ÷ 4 + 6 × 2 = ? 3. 7 + 9 × 3 ÷ 2 - 4 = ? 4. 24 ÷ 6 + 3 × 2 - 1 = ? 5. 18 ÷ 3 + 5 × 2 - 7 = ? 6. 15 + 4 × 5 - 2 ÷ 3 = ? 7. 9 × 2 + 6 ÷ 3 - 8 = ? 8. 20 ÷ 4 + 7 × 3

当然，我们可以使用数学的运算顺序规则来解答这些问题。根据数学中的运算法则，我们首先进行乘法和除法，然后进行加法和减法。下面是每个算式的解答：

1. 5 + 8 × 3 - 2 = 5 + 24 - 2 = 29 - 2 = 27
2. 12 ÷ 4 + 6 × 2 = 3 + 12 = 15
3. 7 + 9 × 3 ÷ 2 - 4 = 7 + 13.5 - 4 = 20.5 - 4 = 16.5
4. 24 ÷ 6 + 3 × 2 - 1 = 4 + 6 - 1 = 10 - 1 = 9
5. 18 ÷ 3 + 5 × 2 - 7 = 6 + 10 - 7 = 16 - 7 = 9
6. 15 + 4 × 5 - 2 ÷ 3 = 15 + 20 - 0.666… ≈ 15 + 20 - 0.67 = 34.33
7. 9 × 2 + 6 ÷ 3 - 8 = 18 + 2 - 8 = 20 - 8 = 12
8. 20 ÷ 4 + 7 × 3 - 5 = 5 + 21 - 5 = 26 - 5 = 21
9. 8 + 5 × 2 - 12 ÷ 3 = 8 + 10 - 4 = 18 - 4 = 14
10. 6 × 3 + 4 ÷ 2 - 5 = 18 + 2 - 5 = 20 - 5 = 15
11. 21 ÷ 3 + 2 × 4 - 7 = 7 + 8 - 7 = 15 - 7 = 8
12. 10 × 2 + 5 ÷ 5 - 3 = 20 + 1 - 3 = 21 - 3 = 18
13. 9 + 6 × 3 - 18 ÷ 2 = 9 + 18 - 9 = 27 - 9 = 18
14. 14 ÷ 2 + 7 × 3 - 8 = 7 + 21 - 8 = 28 - 8 = 20
15. 3 × 4 + 6 ÷ 2 - 5 = 12 + 3 - 5 = 15 - 5 = 10
16. 8 + 5 × 2 - 3 ÷ 2 = 8 + 10 - 1.5 = 18 - 1.5 = 16.5
17. 12 ÷ 3 + 4 × 2 - 7 = 4 + 8 - 7 = 12 - 7 = 5
18. 6 + 8 × 3 - 5 ÷ 2 = 6 + 24 - 2.5 = 30 - 2.5 = 27.5
19. 20 ÷ 4 + 3 × 2 - 9 = 5 + 6 - 9 = 11 - 9 = 2
20. 9 × 3 + 2 ÷ 2 - 6 = 27 + 1 - 6 = 28 - 6 = 22