整十、整百数与0相乘,因数末尾有几个0,积的末尾就有几个0. .
4÷ ==7÷ =20%=8: .
= ÷60=2:5= %= 成.
15: = ÷ ==0.625= %
=== ÷100= %= 成.
3:4==75÷ = %= 折.