999*99*9等于多少?(简便法计算)
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:2024/06/30 23:19:03
999*99*9等于多少?(简便法计算)
rt
不用计算器!
rt
不用计算器!
![999*99*9等于多少?(简便法计算)](/uploads/image/z/4772744-8-4.jpg?t=999%2A99%2A9%E7%AD%89%E4%BA%8E%E5%A4%9A%E5%B0%91%3F%28%E7%AE%80%E4%BE%BF%E6%B3%95%E8%AE%A1%E7%AE%97%29)
999×99×9
=(1000-1)×99×9
=1000×99×9-99×9
=1000×(100-1)×9-(100-1)×9
=900000-9000-900+9
=890109
=(1000-1)×99×9
=1000×99×9-99×9
=1000×(100-1)×9-(100-1)×9
=900000-9000-900+9
=890109