简便运算：（2.5-2.5*0.6）/0.4 31.4*0.65+4.5*3.14-3又50分之7
问题描述：
简便运算：（2.5-2.5*0.6）/0.4 31.4*0.65+4.5*3.14-3又50分之7
答
2.5(1-0.6)/0.4
=2.5*0.4/0.4
=2.5*1
=2.5
31.4*0.65+0.45*31.4-3.14
=31.4*(.65+.45)-3.14
=31.4*1.1-31.4*0.1
=31.4*(1.1-0.1)
=31.4