9+99+999+9999+99999+999999+9999999+99999999+999999999等于多少?
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![9+99+999+9999+99999+999999+9999999+99999999+999999999等于多少?](/uploads/image/z/209879-71-9.jpg?t=9%2B99%2B999%2B9999%2B99999%2B999999%2B9999999%2B99999999%2B999999999%E7%AD%89%E4%BA%8E%E5%A4%9A%E5%B0%91%3F)
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,...
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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。
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