3.8×1.25-1又4分之1+7.2×125%
=3.8×1.25-1.25+7.2×1.25
=(3.8-1+7.2)×1.25
=10×1.25
=12.5
【13又2分之1-（3.8×1.25-1又4分之1+7.2×125%）】÷0.01
=(13.5-12.5)÷0.01
=1÷0.01
=100