Make sure that you've turned on the Num Lock or Caps Lock key when you're trying to type numbers.
Check if "Mouse Keys" is not enabled. Open the Control Panel, next go to Ease of Access > Ease of Access Center and click Make the mouse easier to use. Then uncheck Turn On Mouse Keys.
Uninstall and reinstall the keyboard driver. Press the Windows and R keys at the same time, type devmgmt.msc in the Run box and press Enter. Expand the Keyboards category and right-click on your wireless keyboard driver. Choose Uninstall > Ok, then reboot your PC.