72x0.81+10.4(用简便计算)列递等式
问题描述:
72x0.81+10.4(用简便计算)
列递等式
答
72×0.81+10.4
=(70+2)×0.81+10.4
=70×0.81+2×0.81+10.4
=56.7+(1.62+10.4)
=56.7+12.02
=68.72