72﹣72÷12×5=0÷12×5=0 .
=12÷ =0.25=4: = %
1÷4==4: = %= (小数)
==6﹣ = ÷= 折.
:5=72: =18:15== % .
=0.3: = %= (填小数)= 折= 成.