WaffleGadgets Rabbit's Abacus: Basic Services 1.0 Its a Mathematical Expression Evaluator but in short its a simple calculator. I see it a little more then the kind of calculator that comes with windows. The Rabbit's Abacus designed to be used on a computer workstation enviroment. The calculator that comes with windows its a design that is brought straight down from the handheld calculators that are sold at your local office supply store, and that design is not ergonomically friendly on a computer workstation.