Question

3.45乘以1.2减2.25怎么用简便计算？

Answer 1

3.45 x 1.2 - 2.25 = 3.45 x (1 + 0.2) - 2.25 = 3.45 - 2.25 + 3.45 x 0.2=1.2+3 x 0.2 + 0.45 x 0.2=1.2+0.6+0.09=1.8+0.09=1.89

Answer 2

原式等于3.45×（1+0.2）-2.25
=3.45×1+3.45×0.2-2.25
=3.45+0.69-2.25
=3.45-2.25+0.69
=1.2+0.69
=1.89