①x÷=
②x﹣x=3
5x-= :=x: 7.2+4x=50
19+23=
5﹣1.6=
0.23÷0.1=
0.4×0.2=
=
÷0.25=
5.68﹣0.73﹣0.27
3.25×3.8+67.5×0.38
8×43×125
10﹣0.9= 28+82= 20×5%= +×0=
4.8÷0.8= += ×= 1÷-1=