怎么算方便?113+114+115+116+117999+998+998+997+997+999.
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/07/02 01:13:49
怎么算方便?
113+114+115+116+117
999+998+998+997+997+999.
113+114+115+116+117
999+998+998+997+997+999.
![怎么算方便?113+114+115+116+117999+998+998+997+997+999.](/uploads/image/z/4244461-61-1.jpg?t=%E6%80%8E%E4%B9%88%E7%AE%97%E6%96%B9%E4%BE%BF%EF%BC%9F113%2B114%2B115%2B116%2B117999%2B998%2B998%2B997%2B997%2B999%EF%BC%8E)
(1)113+114+115+116+117
=115×5
=575;
(2)999+998+998+997+997+999
=(1000-1)+(1000-2)+(1000-2)+(1000-3)+(1000-3)+(1000-1)
=1000×5-(1+2+2+3+3+1)
=5000-12
=4988.
=115×5
=575;
(2)999+998+998+997+997+999
=(1000-1)+(1000-2)+(1000-2)+(1000-3)+(1000-3)+(1000-1)
=1000×5-(1+2+2+3+3+1)
=5000-12
=4988.