Make sure that the NumLock key is enabled. If pressing the key once doesn’t enable NumLock, press and hold the key for five seconds.

Verify that the correct keyboard layout is selected in Windows Settings and that the layout matches your keyboard.

You can also try the following:

• Enable and disable other toggle keys such as Caps Lock, Scroll Lock, and Insert while checking if the number keys work on different apps or programs.
• Disable Turn on Mouse Keys on Windows:
  1. Open the Ease of Access Center by clicking the Start key, then click Control Panel, click Ease of Access and then Ease of Access Center.
  2. Click Make the mouse easier to use.
  3. Under Control the mouse with the keyboard, uncheck Turn on Mouse Keys.
• Disable Sticky Keys, Toggle Keys, & Filter Keys on Windows:
  1. Open the Ease of Access Center by clicking the Start key, then click Control Panel, click Ease of Access and then Ease of Access Center.
  2. Click Make the keyboard easier to use.
  3. Under Make it easier to type, make sure all checkboxes are unchecked.
• Verify the product or receiver is connected directly to the computer and not to a hub, extender, switch, or something similar.
• Make sure the keyboard drivers are updated. Learn how to do this on Windows on the Update drivers through Device Manager page.
• Try using the device with a new or different user profile.
• Test the mouse/keyboard or receiver on a different computer.