列递等式 简便 计算:(1)9.81X9.8 (2)0.027+9.9X0.27 (3)13.4-0.4X3
问题描述:
列递等式 简便 计算:(1)9.81X9.8 (2)0.027+9.9X0.27 (3)13.4-0.4X3
答
(1)9.81X9.8
=9.81×(10-0.2)
=98.1-1.962
=96.138
(2)0.027+9.9X0.27
=0.027+99×0.027
=0.027×(1+99)
=0.027×100
=2.7
(3)13.4-0.4X3
=13.4-1.2
=12.2