练习八1.(4÷3/5-5)÷2/3 (5/6+4/9)×18 (2-1/3+2/3)×12=(20/3-5)×3/2 = 5/6×18+4/9×18 = 2×12-1/3×12+2/3×12=20/3×3/2-5×3/2 = 15+8 = 24-4+8= 10-15/2 = 23 = 28= 5/22. 420×(1-1/6)=350(千克)3.(1)180×(1-1/5)=144(米) (2)180×1/5=36(米)4.(1)120×(1+9/10)=228(元) (2)120×(1-3/8)=75(元)5.(1)12/25×(1-1/8)=21/50(吨) (2)12/25-1/8=71/200(吨)6.(1)1/4×(1/8+1/3)=11/96(公顷) (2 |