Question

2.25×5分之3＋1.75÷1又3分之2＋60％

(1＋3分之1＋4分之1）×（3分之1加4分之1＋5分之1）—（1＋3分之1＋4分1＋5分之1）×（3分之1加4分之1） 两题都用简便方法算

Answer 1

2.25×3/5+1.75÷1又2/3+60℅
=2.25×0.6+1.75÷5/3+0.6
=2.25×0.6+1.75×3/5+0.6
=2.25×0.6+1.75×0.6+0.6
=(2.25+1.75+1)×0.6
=5×0.6
=3

(1+1/3+1/4)×(1/3+1/4+1/5)-(1+1/3+1/4+1/5)×(1/3+1/4)
=(1+1/3+1/4)×[(1/3+1/4)+1/5]-[(1+1/3+1/4)+1/5]×(1/3+1/4)
=(1+1/3+1/4)×(1/3+1/4)+(1+1/3+1/4)×1/5-(1+1/3+1/4)×(1/3+1/4)-(1/3+1/4)×1/5
=(1+1/3+1/4)×1/5-(1/3+1/4)×1/5
=[1+(1/3+1/4)]×1/5-(1/3+1/4)×1/5
=1×1/5+(1/3+1/4)×1/5-(1/3+1/4)×1/5
=1/5