Moonmath.js is a package providing the basic lunar arithmetic operations.
Lunar arithmetic, formerly dismal arithmetic, began with a 2011 paper of the same name, authored by David Applegate, Marc LeBrun, and N. J. A. Sloane. It features two defined operations, addition and multiplication, which are only performed on positive whole integers. One does addition by taking a given pair of numbers and selecting the larger one; likewise, multiplication is done by selecting the smaller number.