9÷3=3×7=21+3=24
(9 + 3) × (9 - 7)
(9 + 7 × 9) ÷ 3
(9 + (7 × 9)) ÷ 3
(9 - 7) × (9 + 3)
(9 × 7 + 9) ÷ 3
(9 - 7) × (3 + 9)
(3 + 9) × (9 - 7)
解法:
①(a-b)×(c+d) 如(10-4)×(2+2)=24等
②(a+b)÷c×d 如(10+2)÷2×4=24等
③(a-b÷c)×d 如(3-2÷2)×12=24等
④(a+b-c)×d 如(9+5-2)×2=24等
⑤a×b+c-d 如11×3+1-10=24等
1: (9 + 9 × 7) ÷ 3
2: (9 + (9 × 7)) ÷ 3
3: (9 ÷ 9 + 7) × 3
4: ((9 ÷ 9) + 7) × 3
5: (9 + 3) × (9 - 7)
6: (9 + 7 × 9) ÷ 3
7: (9 + (7 × 9)) ÷ 3
8: (9 - 7) × (9 + 3)
9: (9 × 7 + 9) ÷ 3
10: ((9 × 7) + 9) ÷ 3
11: (9 - 7) × (3 + 9)
12: (3 + 9) × (9 - 7)
13: 3 × (9 ÷ 9 + 7)
14: 3 × ((9 ÷ 9) + 7)
15: 3 × (7 + 9 ÷ 9)
16: 3 × (7 + (9 ÷ 9))
17: (7 + 9 ÷ 9) × 3
18: (7 + (9 ÷ 9)) × 3
19: (7 × 9 + 9) ÷ 3
20: ((7 × 9) + 9) ÷ 3
9÷3=3×7=21+3=24 OK
9×7/3+3