Number Keys in Macbook Air Not Working

The number keys in my Macbook Air has suddenly stopped working. The password in my laptop is alphanumeric. Now I can't open my laptop. What should I do to fix this?

The number keys in my Macbook Air has suddenly stopped working. The password in my laptop is alphanumeric. Now I can't open my laptop. What should I do to fix this?
Is the trackpad working fine? Seems to a hardware problem with the keyboard. Is it still in warranty? If, then look for the replacement.
I think this problem you got here can’t be fixed by a simple software installation and or checking the system using a disk utility application. It is a hardware problem that should be checked by a certified Macintosh hardware technician or by any qualified hardware technician that has already handled Mac computers.
If your Mac PC supports USB devices then you can use a USB-type keyboard for the meantime as a temporary replacement for your Macbook Air’s malfunctioning keyboard. You should also check if the touchpad is still working so you can use a separate mouse in case it also stopped working. If both the touchpad and the keyboard stopped working, you can use separate USB versions of these devices.