Once the data has been entered, all the chips need to be slid down to the bottom row by clicking on the SUM COLUMNS button. In this mode where there are more than one chip in a cell, the chip color will change from red to purple. The decimal value of the sum will be shown in the text box to the right of the bottom row. Obviously since the calculator uses the binary notation for the representation of numbers, it is not appropriate to have more than one chip in any cell. However, two chips in a single cell is equivalent to one chip in the cell to the left. Thus by clicking on a purple cell the manual operation of picking up two chips from a cell and placing one chip in the cell to the left is emulated. You should click on purple chip sets until each cell contains at most one red chip. At the point the proper binary representation will be in the bottom row.