鸡有80只,鸭有100只,鸡和鸭只数的比是 ,比值是 .
3÷ =6÷8= ÷12=51÷ = 填小数.
÷8=21÷ == : = (小数).
÷ ==3: = :24= (填小数)
0.12=== ÷ =24: .
:5=== ÷25= (写小数).