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The sum of all digits of natural number n is Sn, such as n = 38, Sn = 3 + 8 = 11; n = 247, Sn = 2 + 4 + 7 = 13. If n-sn = 2007 is satisfied for some natural numbers, the maximum value of n is () A. 2025B. 2023C. 2021D. 2019
Let n = 2abc = 2000 + 100A + 10B + C, s (n) = 2 + A + B + C. ∵ N-S (n) = 2007, ∵ 2000 + 99A + 9b-2 = 2007, ∵ 99A + 9b = 9, where a and B are integers from 0 to 9, ∵ a = 0, B = 1, ∵ n hundreds
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