Hello,
Many notebook computers have a built-in Num Lock that turns a series of the main keys on the keyboard into a a set of "number pad" keys when pressed. This can usually be toggled on and off by pressing the Shift or Function key, along with the Num Lock key. Usually the former are in the lower-left corner of the keyboard and the latter in the upper-right corner, although that can vary from model to model of notebook.
Regards,
Aryeh Goretsky