Something like Roman numerals for math geeks. Popular with Lisp lovers and one more reason for WhyWeHateLisp.
It is a formalisation of the well-known natural numbers (non-negative integers). Natural numbers are very handy for counting. Peano showed that we don't have to be afraid to run out of them, since there are infinitely many.
Is its popularity with Lisp lovers primarily due to its use in StructureAndInterpretationOfComputerPrograms?
CategoryMath