24点题目：使用数字 3 4 5 12，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36个解（使用交换律变换后算一个解）,
难度系数是2星
★★☆☆☆☆☆☆【
简单24点题目
】。
| 序号 |
题目：3,4,5,12 |
| 1 |
((12 + 3) + 5) + 4 |
| 2 |
((12 + 4) + 3) + 5 |
| 3 |
((12 + 5) + 4) + 3 |
| 4 |
((12 + 5) + 3) + 4 |
| 5 |
((5 × 4) − 12) × 3 |
| 6 |
((12 + 3) + 4) + 5 |
| 7 |
((12 + 4) + 5) + 3 |
| 8 |
(12 + (4 + 3)) + 5 |
| 9 |
(12 + 3) + (5 + 4) |
| 10 |
(12 + (5 + 3)) + 4 |
| 11 |
(12 + (5 + 4)) + 3 |
| 12 |
(12 + 4) + (5 + 3) |
| 13 |
(12 + 5) + (4 + 3) |
| 14 |
12 + ((4 + 3) + 5) |
| 15 |
12 × (3 − (5 − 4)) |
| 16 |
12 + ((5 + 4) + 3) |
| 17 |
12 × ((4 + 3) − 5) |
| 18 |
12 + ((5 + 3) + 4) |
| 19 |
12 × (4 − (5 − 3)) |
| 20 |
((12 × 5) ÷ 3) + 4 |
| 21 |
(12 ÷ (5 − 3)) × 4 |
| 22 |
(5 + (12 ÷ 4)) × 3 |
| 23 |
(5 × (12 ÷ 3)) + 4 |
| 24 |
(12 × 4) ÷ (5 − 3) |
| 25 |
(5 + 3) × (12 ÷ 4) |
| 26 |
(12 × (5 + 3)) ÷ 4 |
| 27 |
(5 × 4) + (12 ÷ 3) |
| 28 |
12 × (4 ÷ (5 − 3)) |
| 29 |
12 × ((5 + 3) ÷ 4) |
| 30 |
(5 ÷ (3 ÷ 12)) + 4 |
| 31 |
(5 + 3) ÷ (4 ÷ 12) |
| 32 |
(12 ÷ (3 ÷ 5)) + 4 |
| 33 |
(12 × (5 ÷ 3)) + 4 |
| 34 |
12 ÷ ((5 − 3) ÷ 4) |
| 35 |
12 ÷ (4 ÷ (5 + 3)) |
| 36 |
4 ÷ ((5 − 3) ÷ 12) |