两个质数的和是10,积是21,它们是 和 .
5:4=______÷20=______%=
9÷______=75%=______:8==______(填小数)
=______÷______=60%=______:______=______小数.
2.5:______==1.25=25÷______=______%.
3:5==15÷______=______÷75=______(填小数)