_CALCULATOR is a scientific calculator that can be integrated with other AMOS programs. The file _CALCULATOR.AMOS contains the calculator procedure and the supplementary procedures it uses for interactive help (accessed by clicking on a button with the right mouse button). The calculator features memory, trigonometrical functions and a doodle area. It runs on its own screen (6) and can be dragged over screens in the background. Its colour scheme is easy to adjust to match more closely the style of the program it is running over (a number of colour schemes, including AMOS and Intuition, are supplied with the procedure). The procedure once featured on an Amiga Format coverdisc (AFCD33).