小红要买8枝笔,用的钱数和笔的单价成反比例. .
12÷ =0.25= %= :24== (填成数)
9÷ == :8= (填小数)
20: = ÷20==0.8= %
==36÷ = (填小数)
18: =0.25= %= ÷24=.