24点题目：使用数字 2 3 4 9，利用加减乘除、括号算出24。数字顺序可以任意调换，下面列出所有可行算式。
本题共有39个解（使用交换律变换后算一个解）,
难度系数是3星
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中等偏易24点题目
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| 序号 |
题目：2,3,4,9 |
| 1 |
(9 + 3) × (4 − 2) |
| 2 |
((9 × 2) ÷ 3) × 4 |
| 3 |
((9 × 4) ÷ 3) × 2 |
| 4 |
((9 × 2) × 4) ÷ 3 |
| 5 |
((9 ÷ 3) × 2) × 4 |
| 6 |
((9 × 4) × 2) ÷ 3 |
| 7 |
((9 + 3) × 4) ÷ 2 |
| 8 |
((9 + 3) ÷ 2) × 4 |
| 9 |
(9 × (4 × 2)) ÷ 3 |
| 10 |
(9 + 3) × (4 ÷ 2) |
| 11 |
(4 × (9 ÷ 3)) × 2 |
| 12 |
(4 × 2) × (9 ÷ 3) |
| 13 |
(9 ÷ (3 ÷ 4)) × 2 |
| 14 |
(9 + 3) ÷ (2 ÷ 4) |
| 15 |
(9 ÷ (3 ÷ 2)) × 4 |
| 16 |
(9 × 4) × (2 ÷ 3) |
| 17 |
(9 × 4) ÷ (3 ÷ 2) |
| 18 |
(9 × 2) ÷ (3 ÷ 4) |
| 19 |
(4 ÷ (3 ÷ 9)) × 2 |
| 20 |
(2 ÷ (3 ÷ 9)) × 4 |
| 21 |
(9 × 2) × (4 ÷ 3) |
| 22 |
(9 × (4 ÷ 3)) × 2 |
| 23 |
(9 × (2 ÷ 3)) × 4 |
| 24 |
(4 × 2) ÷ (3 ÷ 9) |
| 25 |
9 × (4 × (2 ÷ 3)) |
| 26 |
9 × ((4 × 2) ÷ 3) |
| 27 |
9 × (2 × (4 ÷ 3)) |
| 28 |
9 × (4 ÷ (3 ÷ 2)) |
| 29 |
9 ÷ (3 ÷ (4 × 2)) |
| 30 |
4 ÷ (2 ÷ (9 + 3)) |
| 31 |
9 ÷ ((3 ÷ 4) ÷ 2) |
| 32 |
9 ÷ ((3 ÷ 2) ÷ 4) |
| 33 |
2 ÷ ((3 ÷ 4) ÷ 9) |
| 34 |
2 ÷ ((3 ÷ 9) ÷ 4) |
| 35 |
4 ÷ ((3 ÷ 2) ÷ 9) |
| 36 |
9 × (2 ÷ (3 ÷ 4)) |
| 37 |
4 ÷ ((3 ÷ 9) ÷ 2) |
| 38 |
4 ÷ (3 ÷ (9 × 2)) |
| 39 |
2 ÷ (3 ÷ (9 × 4)) |