2013 UMO Problems/Problem 3

Problem

Find all $x$ with $1 \le x \le 999$ such that the last three digits of $x^2$ are all equal to the same nonzero digit.

Solution

See Also

2013 UMO (ProblemsAnswer KeyResources)
Preceded by
Problem 2
Followed by
Problem 4
1 2 3 4 5 6
All UMO Problems and Solutions