笼子里有鸡和兔共8只,数脚一共20只,鸡有 只,兔有 只.
÷ = :16=5÷ = %=0.25.
0.8=12÷ = :10= %
÷ =8﹕ = ﹕15==.
%=15÷ ==0.3: =0.75= 折= (填成数).
÷ ==.