学校买了2盒钢笔,每盒10枝,每枝钢笔12元.一共用了多少元?
3÷ ==0.75=6: = %
3÷ ==0.6=6: = %.
3:5==9: == .
=0.375=12÷ = %=0.45= %= ÷ .
= ÷ = = % ÷ =0.25== %