On a board there are $4$ positive integers $a, b, c$ and $d$.
Source: Moldova EGMO TST 2021
February 4, 2023
combinatorics
Problem Statement
On a board there are positive integers and . Dan chooses three of them and writes their product on a paper. Then he substracts from the other number. He does this until appears on the board. What are the possible values of the sum of the numbers written on the paper?