Keypads; Using The Internal Keypad - HP Compaq NC6140 Hardware Manual

Keypads

The notebook has an internal numeric keypad and supports an
optional external numeric keypad or an optional external
keyboard that includes a numeric keypad.

Using the Internal Keypad

The notebook keyboard contains 15 keys that can be used like the
keys on an external keypad.
When the internal keypad is turned on, each key on the internal
keypad performs the functions indicated by the icon in the upper
right corner of the key.
The standard functions of the internal keypad keys can still be
accessed while the keypad is turned on.
Identifying the internal keypad keys
Hardware Guide
Pointing Device and Keyboard
2–13