Two young mathematicians investigate the arithmetic of large and small numbers.

Check out this dialogue between two calculus students (based on a true story):
Devyn
Hey Riley, I’m having a little trouble with this limit
Riley
Well, just plug in and see what you get, right?
Devyn
I tried that, here’s what I got...
Riley
Hm, so that... equals 1 right? I mean, anything divided by itself must be 1?
Devyn
I was thinking the same thing. Initially. But then I tried simplifying stuff first and look what happened.
Riley
Ok... so the answer is 4? Or is it 1? It can’t be both right?
Devyn
Right, that’s why I’m stuck.
Riley
Well, we originally thought it was 1 because it was “a number divided by itself.” But that number was zero, and dividing by zero is usually where things go wrong in math.
Devyn
Good point. Come to think of it, I can’t just plug in the limit value because that only works when the function is continuous at that point. And I can’t evaluate the top and bottom separately like that, because that limit law only works when the bottom isn’t zero. Crap, I really messed that one up, the limit must be then. Thanks!
Devyn
...
Devyn
Also, uh, don’t mention this conversation to anybody ok?
Riley
What conversation?
Devyn
Exactly.
Consider the function
Consider the function
Consider the function