4 CALCULATED INDUSTRIES’ Seton Model Calculators Battery Replacement instructions Towards the top of the back of your calculator, you will find a total of four screws. The upper two screws are only for the display. Do not remove them. The lower two of the four screws are what hold the calculator together. Go ahead and remove them. Once you have removed the two lower screws, you are ready to pull the two halves of the calculator apart. There are two methods for separating the two halves.