Question

7.5乘以2.3加1.9乘以2.5加12.5乘以0.4的简便运算

Answer 1

7.5×2.3+1.9×2.5+12.5×0.4
=2.5×6.9+1.8×2.5+2.5×2
=2.5×（6.9+1.8+2）
=2.5×10.7
=2.5×10+2.5×0.7
=25+1.75
=26.75