你能用简便方法计算下面的题吗?
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:2024/04/30 01:02:14
你能用简便方法计算下面的题吗?
999×999+1999;
87×64+108×29.
999×999+1999;
87×64+108×29.
(1)999×999+1999
=(1000-1)×999+1999
=999000-999+1999
=999000+(1999-999)
=999000+1000
=1000000;
(2)87×64+108×29
=87×64+3×36×29
=87×64+87×36
=87×(64+36)
=87×100
=8700.
=(1000-1)×999+1999
=999000-999+1999
=999000+(1999-999)
=999000+1000
=1000000;
(2)87×64+108×29
=87×64+3×36×29
=87×64+87×36
=87×(64+36)
=87×100
=8700.