8筐白菜,以每筐25千克为准,超过的千克数记作正数,不足的千克数记作负数,称重的记录如下: 1.5,-3,2,-0.5,1,-2,-2,-2.5,8筐白菜的总重量是多少?
问题描述:
8筐白菜,以每筐25千克为准,超过的千克数记作正数,不足的千克数记作负数,称重的记录如下:
1.5,-3,2,-0.5,1,-2,-2,-2.5,8筐白菜的总重量是多少?
答
1.5+(-3)+2+(-0.5)+1+(-2)+(-2)+(-2.5)
=[1.5+1+(-2.5)]+[2+(-2)]+[(-3)+(-2)+(-0.5)]
=0+0+(-5.5)
=-5.5
25×8+(-5.5)=194.5(千克),
答:8筐白菜的总重量是194.5千克.