3×=
3.14×20=
3.6÷0.9=
125%×80=
81÷=
16:8=
99×0.8+0.8=
[1-(+)]÷ 2÷× (8.9-7.7)÷0.2×0.15
+×+ 7.5×+2.5÷
2.4×(1.01-0.88)÷0.52 1.2+〔(0.5-)×1.8〕