Fossil WRIST PDA User Manual page 70

Using Calculator
70 Wrist PDA User Guide
Places the current number in memory. Each new number
you enter with the M+ button is added to the total stored in
memory. The number that you add can be either a
calculated value or a number you enter. Tapping this button
has no effect on the current calculation (or series of
calculations); it merely places the value into memory until it
is recalled.
Recalls the stored value from memory and inserts it in the
current calculation.
Clears any value that is stored in Calculator memory.