Question

(30-19.8)×0.6+31.2简便运算答案

简便运算！

Answer 1

给你个不算简便但是有意思的逆向算法：
(30-19.8+52)×0.6
=((82-20)+0.2)×0.6
=62×0.6+0.12
=37.2+0.12
=37.32

Answer 2

(30-19.8)×0.6+31.2
=(30-20+0.02)X0.6+31.2
=(10+0.02)X0.6+31.2
=10x0.6+0.02X0.6+31.2
=6+0.012+31.2
=37.212
请采纳，不懂可追问

追问

真不好意思，我对过答案。得数是错的（37.32）但演算过程我还是不懂，请指教！

追答

不好意思，我写错了
(30-19.8)×0.6+31.2
=(30-20+0.2)X0.6+31.2
=(10+0.2)X0.6+31.2
=10x0.6+0.2X0.6+31.2
=6+0.12+31.2
=37.32