QMentat

QMentat is a program to help you practice mental arithmetic. It uses arbitrary length fixed point arithmetic and can handle any size numbers, only limited by the size of your screen (and in the case of division with an integer result, the speed at which the number can be factored). It is also quite configurable, allowing you to tailor the questions to your needs. Currently, you may practice any of these operations like addition, subtraction, multiplication, division, powers, and roots.