Anita 1233D

Despite the rather large collection of buttons on what is otherwise a desk calculator, it is possible to figure out their function fairly quickly without the use of a manual.

The three columns on the right represent the accumulation memories, each has its own operational buttons to add, subtract and clear, the diamond button recalls the value. above each column is a lamp to indicate that the memory holds a value. Additionally, the first two of these memories both have a toggle switch above which can enable accumulation of other calculations. in this case percentages and item multiplies respectively.

The only non simple operation performed by this model is square root. notice the machine has twelve nixie digits (plus sign) and is accurate to these twelve. indeed the INS button (stands for inspect) displays the 12 significant digits unfloated. ie it throws away any leading zeros.