-= ×= ×18= +=
3÷= 21×= ÷= ÷=
÷8= 1÷×6= -÷= ÷×0=
×3= 27÷ = 0.22= 40%÷20=
×= 1.4×= ×= 1﹣13÷16= ÷0.25=
0÷= 42×= ÷7= ÷= +×7=
∶
0.5千米∶25米
1.2∶8
= 1.8-40%= 12÷=
×72%= 3.5×= -×=
×50%=
8÷=
4.2×=
1-=
÷15=
2.4÷=
+=
1÷=
×÷×=