求比值:⑴42:56;⑵0.35:0.5;⑶:;⑷0.35:7
1.8×2.4- 1.8×0.24= 180×2.4= 180×0.24= 0.18×0.24= 0.18×0.24=
x : =:
x - x=18.7
15.8-(6+÷12.5%)
10-÷×1