0.64×25×7.8+2.2 的简便运算

分类: 作业答案 • 2022-02-14 22:50:33

问题描述：

答

原式=0.8*0.8*25*(10-2.2)+2.2
=0.8*20*(10-2.2)+2.2
=160-2.2*15
=127

答

0.64×25×7.8+2.2
=0.16*4*25*7.8+2.2
=0.16*100*7.8+2.2
=16*7.8+2.2
=15*7.8+7.8+2.2
=15*(8-0.2)+10
=120-3+10
=127

答

=16*0.04*25*7.8+2.2
=16*1*7.8+2.2
=15*(8-0.2)+7.8+2.2
=120-3+10
=127