24点题目：使用数字 1 4 7 13，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42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：1,4,7,13 |
| 1 |
((13 + 7) × 1) + 4 |
| 2 |
((13 + 4) + 7) × 1 |
| 3 |
((13 × 1) − 7) × 4 |
| 4 |
((13 − 7) × 4) × 1 |
| 5 |
((13 + 7) + 4) × 1 |
| 6 |
((13 × 1) + 7) + 4 |
| 7 |
((13 × 1) + 4) + 7 |
| 8 |
((13 − 7) × 1) × 4 |
| 9 |
((13 + 4) × 1) + 7 |
| 10 |
(13 + 7) + (4 × 1) |
| 11 |
(13 + (7 + 4)) × 1 |
| 12 |
(13 − (7 × 1)) × 4 |
| 13 |
(13 × 1) + (7 + 4) |
| 14 |
(13 − 7) × (4 × 1) |
| 15 |
(13 + (7 × 1)) + 4 |
| 16 |
(13 + (4 × 1)) + 7 |
| 17 |
(13 + 4) + (7 × 1) |
| 18 |
13 + ((7 × 1) + 4) |
| 19 |
13 + ((7 + 4) × 1) |
| 20 |
13 + (7 + (4 × 1)) |
| 21 |
((13 + 7) ÷ 1) + 4 |
| 22 |
((13 ÷ 1) − 7) × 4 |
| 23 |
((13 − 7) × 4) ÷ 1 |
| 24 |
((13 + 7) + 4) ÷ 1 |
| 25 |
((13 + 4) ÷ 1) + 7 |
| 26 |
((13 ÷ 1) + 7) + 4 |
| 27 |
((13 − 7) ÷ 1) × 4 |
| 28 |
((13 ÷ 1) + 4) + 7 |
| 29 |
((13 + 4) + 7) ÷ 1 |
| 30 |
(13 − 7) × (4 ÷ 1) |
| 31 |
(13 ÷ 1) + (7 + 4) |
| 32 |
(13 − (7 ÷ 1)) × 4 |
| 33 |
(13 + (7 + 4)) ÷ 1 |
| 34 |
(13 + 7) + (4 ÷ 1) |
| 35 |
(13 + (7 ÷ 1)) + 4 |
| 36 |
(13 + 4) + (7 ÷ 1) |
| 37 |
(13 + (4 ÷ 1)) + 7 |
| 38 |
13 + ((7 ÷ 1) + 4) |
| 39 |
13 + (7 + (4 ÷ 1)) |
| 40 |
13 + ((7 + 4) ÷ 1) |
| 41 |
(13 − 7) ÷ (1 ÷ 4) |
| 42 |
4 ÷ (1 ÷ (13 − 7)) |