已知两个因数的积是75.6,其中一个因数是21,另一个因数是 .
9÷ == :8= (填小数)
20: = ÷20==0.8= %
==36÷ = (填小数)
18: =0.25= %= ÷24=.
2.5==50÷ = ÷50.