Question

3.87+12.5×4.2-0.8简便计算

Answer 1

3.87+12.5×4.2-0.8
=3.87+12.5×（亮袭野4+0.2）禅袜-0.8
=3.87+12.5×（4+0.2）敬喊-0.8
=3.87+50+2.5-0.8
=55.57

Answer 2

计算睁庆手差大如悉嫌下：
3.87+12.5×4.2-0.8
=3.87+12.5×4+12.5×0.2-0.8
=3.87+50+2.5-0.8
=53.87+2.5-0.8
=53.87-0.8+2.5
=53.07+2.5
=55..57