(5.7-2.8)×(2.5+2.7) 用简便算法计算!_数学解答

(5.7-2.8)×(2.5+2.7) 用简便算法计算!

人气：342 ℃　时间：2020-02-03 22:12:16

解答

=(6-0.3-3+0.2)*(3-0.5+3-0.3)
=(3-0.1)*(6-0.8)
=3*6-0.1*6-3*0.8+0.1*0.8
=18-0.6-2.4+0.08
=18-(0.6+2.4)+0.08
=18-3+0.08
=15.08