p x q x s(r) = p x s(q) x r = s (p) x q x r, 2 digits numbers, s= sum of digits
Source: 2021 Czech-Polish-Slovak Match Junior, team p6 CPSJ
September 12, 2021
number theorysum of digits
Problem Statement
Let denote the sum of digits of a positive integer . Using six different digits, we formed three 2-digits such that Find all such numbers .