已知a:b=c,那么(a+m):(b+m)=c(m≠0) .
=0.25=4÷ = :28= %
12÷ ==== %= 折.
5: ==1.25=30÷ = %
1==3÷ = : = %= (填小数).
=2: =4÷ = %=0.4.