The Devil's Calculator is a mathematical puzzle full of logic brain teasers. An evil calculator has its normal arithmetic operators replaced with sadistically obscure functions. You must figure out (with logic and a bit of algebra) how to use these corrupted operators.

Play involves discovering what each mysterious operator does on the calculator so you get get the result 666 and move on to the next level. This starts with trial and error. You enter a number then press the mystery function to see the result. In this way you build up information to help you identify what the function does. As soon as you are able to get the "666" result you move to the next level.

This starts simply, with early functions simply adding a number to the result. But as you progress the function becomes more complex. Also, different keys are on fire and can't be used. With this increased challenge you get different ways to visualise your test results on graphs.

The result is an unusual and engaging way to learn a range of different mathematical processes and methods.