首先:2.4x÷(2x-0.7)×(2x-0.7)=1.2
3.2a﹣0.2a=
2.8+3.5=
10﹣2.3=
0.25×40=
0.45÷0.3=
1.1×0.9=
1.6÷0.1=
1.5÷0.05=