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PUMaC 2015 · 数论（B 组） · 第 1 题

PUMaC 2015 — Number Theory (Division B) — Problem 1

专题
Discrete Math / 离散数学
难度
L3
来源
PUMaC

题目详情

  1. [ 3 ] What is the remainder when 100 ∑ k 10 k =0 is divided by 9? n
解析
  1. [ 3 ] What is the remainder when 100 ∑ k 10 k =0 is divided by 9? Solution: The sum of the digits of the expression is 101, so by the rule for remainder modulo 9, the answer is 101 (mod 9), or 2 . Author: Eric Neyman n