a+b-c-d be a multiple of 2013, 6 numbers from a set of 63 < = 2012
Source: Danube 2013 junior p2
July 22, 2019
number theorycombinatoricsmultipleSum
Problem Statement
Consider distinct natural numbers, at most equal to . Show that it is possible to choose four of them, denoted as such that to be a multiple of