Math is based on axioms. Good solid axioms, yet axioms nonetheless. Math is purely our way of describing and quantifying our surroundings. Drakoblare is correct in that regard.

Religious syncretism is a thing that happens. The way that Islam syncretised with Hindu beliefs in Java for example. If it happens in any religion but Christianity--for example, the later Norse wore thor's hammers that look like crosses--then that's intriguing and fascinating. If Christianity absorbs the other local beliefs in an area, it's called emotionally-charged words like stealing.

This is why atheists come off as butthurt. I'm an atheist, btw, but I don't truck with anger directed at natural blending of beliefs. Syncretism is not stealing, it is not a planned operation, and it is not confined to Christianity by any means.