①（

5

9

×45-0.4）÷0.4
=（25-0.4）÷0.4，
=24.6÷0.4，
=61.5．
答：商是61.5．
②（28+32）÷

4

5

．
=60÷

4

5

，
=75．
答：这个数是75．