How to solve this equation?

[polymath257]

Hey, they don't even want arabic numbers to be taught in our school system......

A subject dealing group homo-morphisms would definitely be something they would dislike.

Math humor:

1. What's purple and commutes? An abelian grape.

2. What's yellow and equivalent to the axiom of choice? Zorn's lemon.

I think I have a by orders of magnitude funnier math joke (actually an anecdote from my student life), which I posted on Reddit:

Today, at the university (I study Computer Science), we were taught about the set theory. The professor (who is, by the way, called Radoslav Galić) was explaining to us why the cardinal number of a union of sets is not always equal to the sum of the cardinal number of sets in that union: "If that were true, a dog should have eight legs. A dog, namely, has two front legs, two hind legs, two left legs and two right legs. The sum of the cardinal numbers of those sets is eight (four times two), but the cardinal number of the union of those sets is, of course, four."

My joke is at least understandable to a broader audience, your jokes are not.

Sure. And there are various levels of math joke, from the mathematical spy that was caught because he was told the sine and didn't know the cosine. But that's off on a tangent.

Then there are the snakes on Noah's arc that didn't go forth to multiply be cause they were adders. But later, they had kids beside a fallen tree: adders can multiply by logs.

Then there is the proof that all horses are the same color (by induction). And the proof (like that above for dogs) that horses have at least 12 legs, which gives a horse of a different color, a contradiction.