7.6＊5.1+76＊0.4
=76＊0.51+76＊0.4
=76＊（0.51+0.4）
=76＊0.91
=69.16
7.6×5.1+76×0.4=7.6×(5.1+4)=7.6×9.1=7.6×(10-0.9)=76-7.6+0.76=69.16
