0.22=
6.8+1.28=
0.5÷0.25=
50×30%=
1﹣1÷7=
6÷=
×24=
2008﹣199=
+=
2.5×0.7×0.4=
①(+-)÷
②125%×3.2×25
③19.43-(9.43+6.89)
④×80%+÷1