Calculator

A calculator could be used to perform mathematical calculations.

The Second Doctor elected to use an abacus to calculate the stability of bubbles within a singularity rather than a calculator as the latter's accuracy could be affected by the singularity. (AUDIO: The Dead Star ^[+]Loading...["The Dead Star (audio story)"])

At Brendon School, Vislor Turlough had a digital watch which could also function as a calculator. (AUDIO: Power Game ^[+]Loading...["Power Game (audio story)"])