Chalkboard is powerful calculator with unique feature - it evaluates mathematical expressions step by step. It uses a different approach from a conventional calculator, which is more natural to the way people calculate. When you calculate on a conventional calculator, each time you enter a new number you lose sight of the previous one. And if you make a mistake in the middle of a long expression, you have to start all over. In Chalkboard, you can see all of what you are calculating and expressions can easily be built and edited.