因为8÷0.4=20,所以8是0.4的倍数,0.4是8的约数 .
15: = ÷ ==0.625= %
=== ÷100= %= 成.
3:4==75÷ = %= 折.
3:4== ÷12= %= (填小数)
÷15=0.8== %