4.2*1.2-5.2*0.7 怎么简便计算
问题描述:
4.2*1.2-5.2*0.7 怎么简便计算
答
4.2*1.2-5.2*0.7
=4.2*1.2-(4.2+1)*0.7
=4.2*0.5-0.7
=2.1-0.7
=1.4
答
0.7*6*1.2-5.2*0.7
=(7.2-5.2)*0.7
=2*0.7
=1.4