The purest branch of maths. Not science, not that boring stuff they teach you in school. Maths!
In recreational maths, we look at the curiosities that are held within sequences, such as the Fibonacci Sequence, numbers, such as happy or lucky numbers, and formula, such as the 'Everything Formula', not to mention geometry, algebra, trigonometry and so many other facts and puzzles concerned with maths alone. And of course, this is the number 0! (1) place for it all.