5.4平方千米= 公顷= 平方米 3小时45分= 小时.
÷7=÷ =38.
× =× = ×= ×0.1=+ = ﹣.
× =× =+ =1.5× =× =1.
× =3600 × =3600 × =3600 × =3600 × =3600.
× = ÷=+ =1.