简便计算:28×3.5+2.8×75-28
问题描述:
简便计算:28×3.5+2.8×75-28
答
28x3.5+2.8x75-28=28x3.5+28x7.5-28=28x(3.5+7.5-1)=28x10=280
答
28x3.5+2.8x75-28
=28x(3.5+7.5-1) 注:2.8x75=28x7.5
=28x10
=280