And you could sit for hours realising that Prime numbers are found adjacent a multiple of 6, sometimes in pairs.

Gradually you begin to build up a complex "Sieve of Eratosthenes" using expressions which compound upon 6, and compound further upon what you've produced! Futility.

But you're a maths guy when you draw up spreadsheets to help solve/create problems like:

Balanced Stellar,

Pan Magic and

Edge Numbered Cube.

I wasted too much time trying to do what Charlie did with his program, but the spreadsheet was too slow, too many considerations, but it would have gotten there.

So, "You know you are a math guy when . . ."

you trivialise when there are important things to be done! (Ok! You can have some recreation!)