I was reading this answer to an amusing comic related question: http://math.stackexchange.com/a/166891/35132 and I understand that in the linked answer, the examples of how four may be expressed used base (expressed in decimal!!) is 10, 4, 3 for 4, 10, 11.
What I can't figure out is what base would need to be used for his last example (100) to equal 4 in decimal?
P.S. Are maths questions like this always this hard to put in words?!