用4 7 8 9组成24要1个
问题描述：
用4 7 8 9组成24要1个
急啊!
要2个
答
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)11:4 ...