Here's a couple of

math rhymes I know:

I used to think math was no fun

'Cause I couldn't see how it was done

Now Euler's my hero

And I now see why zero

Equals e^{iπ}+1

'Tis a favorite hobby of mine

A new value of pi to assign

I would fix it at three

For it's easier, you see

Than 3.14159

Rascally Kitten tells me that Harvey L. Carter wrote that second one. Excellent!