2 × (3 × 7 - 9) (3 × (7 - 2)) + 9(3 × (9 + 7)) ÷ 29 - ((2 - 7) × 3)采纳我吧！！
1: 2 × (3 × 7 - 9) 2: 2 × ((3 × 7) - 9) 3: 2 × (7 × 3 - 9)
