(-5)*(+7 1/3)+7*(-7 1/3)-(+12)*(-7 1/3)=多少?(要用简便方法)
问题描述:
(-5)*(+7 1/3)+7*(-7 1/3)-(+12)*(-7 1/3)=多少?(要用简便方法)
答
(-5)*(+7 1/3)+7*(-7 1/3)-(+12)*(-7 1/3)
= (- 5 - 7 + 12)*(+7 1/3)
= 0 *(+7 1/3)
= 0