甲数是乙数的九分之七,甲乙两数的和是80,甲数是 .
= ÷25=40%= :45.
24: == ÷1.2= 折=75%
= ×=36÷ = :13.5.
÷20=0.4= %=2: .
已知m÷n=7…1,则m÷n=.