MacBook keyboard behaving like numb pad

Hi,

Using high sierra, only just noticed this problem as most of the time are use an external keyboard. The right half of my MacBook Pro’s keyboard seems to be behaving as if it’s a numpad. I cannot type letters with it and when I switch keyboard help on and press, for example, “m”, VO says “zero“.

Does anyone know anything about this? I’m hoping there is a setting somewhere I can alter and go back to being able to use my keyboard as a proper keyboard. It behaves properly before logon.