0.75*15+4.5*2.5 3.6*31.4+43.9*6.4 简便计算

问题描述:

0.75*15+4.5*2.5 3.6*31.4+43.9*6.4 简便计算

0.75*15+4.5*2.5
=45/4+45/4=45/2=22.5
3.6*31.4+43.9*6.4
=(1-6.4)*31.4+43.9*6.4
=31.4-6.4*(43.9-31.4)
=31.4-32/5*5/2
=31.4-16
=15.4