Question 10
From the digits $3$, $7$, $1$, $9$, $0$ and $4$ Mila formed the biggest and the smallest six-digit number using each digit exactly once in each of the two numbers. Then she reduced their difference $9$ times. Which number did she get?
Math Olympiad Vault · MathNet 2008-part-03 — 165 problems (EN–VI)