9+99+999+9999+99999+999999+9999999+99999999+999999999等于多少?
来源：学生作业帮助网 编辑：六六作业网 时间：2024/12/27 10:54:44
9+99+999+9999+99999+999999+9999999+99999999+999999999等于多少?
9+99+999+9999+99999+999999+9999999+99999999+999999999等于多少?
9+99+999+9999+99999+999999+9999999+99999999+999999999等于多少?
9+99+999+9999+99999+999999+9999999+99999999+999999999
＝10-1+100-1+1000-1+10000-1+……+1000000000-1
＝1111111101
很简单，等于1111111101
9+99+999+9999+99999+999999+9999999+99999999+999999999
=10-1+100-1+1000-1+.......+1000000000-1
=1111111111-9
=1111111101
9+99+999+9999+99999+999999+9999999+99999999+999999999
＝（9+1）+（99+1）+（999+1）+（9999+1）+（99999+1）+（999999+1）+（9999999+1）+（99999999+1）+（999999999+1）-9
＝1111111110-9
＝1111111101
这题可以用凑数法计算，...
全部展开
9+99+999+9999+99999+999999+9999999+99999999+999999999
＝（9+1）+（99+1）+（999+1）+（9999+1）+（99999+1）+（999999+1）+（9999999+1）+（99999999+1）+（999999999+1）-9
＝1111111110-9
＝1111111101
这题可以用凑数法计算，也可以用拆分数字法计算。
收起