100与80的和,除以它们的差,商是多少?列式为100+80÷100﹣80. .(判断对错)
:5=0.6== ÷60= %
= ÷16= %
7:8= = = %= 填小数.
:15==15÷ = %
0.75=30: = ÷12= %