(7+8-9)*4=24
(5-7/7)*6=24
(4+8)(9-7)
(5-7/7)6
(7+8-9)*4
(5-7/7)*6
1.(7+8-9)*4=24
2.{5-(7/7)}*6=24
(1)
1: 4 × (7 + 8 - 9)
2: 4 × ((7 + 8) - 9)
3: 4 × (7 + (8 - 9))
4: 4 × (7 - 9 + 8)
5: 4 × ((7 - 9) + 8)
6: 4 × (7 - (9 - 8))
7: 4 × (8 + 7 - 9)
8: 4 × ((8 + 7) - 9)
9: 4 × (8 + (7 - 9))
10: (4 + 8) × (9 - 7)
(2)
1: (5 - 7 ÷ 7) × 6
2: (5 - (7 ÷ 7)) × 6
3: 6 × (5 - 7 ÷ 7)
4: 6 × (5 - (7 ÷ 7))
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