学校买来a个足球,每个m元,又买来b个排球,每个n元,一共用去( )元,足球比排球多用( )元.
:20==3: =0.75= %
0.125== :16=5÷ .
= :24=0.5= ÷8=.
6÷ == %== : .
= %=6: == (写小数)