[Zumzoa]

I passed this 'test'/suggested a clever way of solving it at a relatively early age, but have always been pretty poor at Maths. I think it's more indicative of a problem-solving intuition than maths skill, or even thew child's conception of integers.

[thiagofm]

If you didn't notice, he was joking due the fact that there's a story which Gauss did the same,