345﹣298= 0.64÷0.8= ﹣ = × =
1÷0.05= 0.25×40= 2÷ = ×25%=
﹣5,+3,﹣3.5,0.75,﹣
每个小正方形的面积/cm2
4
9
16
所需小正方形的数量/个
216
96
54