4.21×（-七分之四）+七分之四×（-2.79）+8×一百分之一×125 简便运算
问题描述：
4.21×（-七分之四）+七分之四×（-2.79）+8×一百分之一×125 简便运算
答
4.21×（-4/7）+4/7×（-2.79）+8×1/100×125
=-4/7X(4.21+2.79)+8X125X1/100
=-4/7X7+1000X1/100
=-4+10
=6