甲数加上乙数,等于甲数减去乙数的倒数. .
==6﹣ = ÷= 折.
:5=72: =18:15== % .
=0.3: = %= (填小数)= 折= 成.
:12= ÷8=0.75== %
÷12=25%=9÷ = : =.