Use the mouse or your numeric keypad.  This calculator is algebraic. Example: If you enter 3+2*6 into a non-algebraic calculator you will get 30 for your answer. Using this algebraic calculator 3+2*6 will produce 15 as your answer. This is because (as we are sure you remember from high school) in an algebraic equation multiplication is performed before addition.

TIP: Call the calculator from almost anywhere in the program by pressing F11.