23×2又2分之1+0.77÷40%
=23×2.5+0.77×2.5,虽然能用乘法分配率,但并非是能简算.因为23+0.77中可能某个数的小数点打错了.
=﹙23+0.77﹚×2.5
=23.77×2.5
=59.425