17500m2=hm2 2.05km2=hm2
6.6÷0.6= 1.8×0.2= 0.48÷0.6=
3.46+2.54= 1÷0.2= 2-1.7=
0.8×10.1= 2.4×0.5= 2.7÷9= 0.7×0.8=