9的3倍是 ;9是3的 倍;42里面有 个6.
3÷ ==0.375= :24=24: .
=2.5:( )=125%=20÷( )=.
5: ==0.25= %
2.5÷ ==15: = %= (小数)
÷8==0.375=9÷ =;填质数:21= + ; = × .