INTERACTIVE WRISTWATCH CALCULATOR Abstract of the Disclosure An apparatus is disclosed comprising an electronic wrist-watch and a multifunction electronic calculator in a single wrist mountable case having a common display and keyboard. The watch portion of the watch/calculator includes time of day, calendar, stopwatch and alarm functions. Each of these functions can be controlled from the keyboard on the watch/calculator. The electronic calculator portion of the watch/calculator performs the four standard arithmetic functions: add, subtract, multiply and divide; and has an extra storage register. The calculator portion can perform calculations with scalar quantities entered via the keyboard or stored in the calculator as well as calcula-tions with time interval and real time data from the watch portion. During the time that calculations are not being performed the cal-culator goes into a sleep or inactive mode in order to minimize the amount of battery power used by the watch/calculator.