How can I use alt codes without a numpad, and also no numpad on the on-screen keyboard?

I tried looking it up but the only solution I found was to use the on-screen keyboard. However, there is no numpad on the on-screen keyboard, as well. It just looks exactly like my laptop's keyboard. And there's no num lock, either. It'd help greatly if I could be able to use alt codes since I'm learning languages.