Advice on how to deal with uneven floor

[dd1111]

Hi there.

I just moved into new flat, and to be honest I didnt pay enough attention at the time, but now i see there is actually a carpet in the kitchen (I know that is pretty big not to spot that).

But anyways I want to temporarily pull off the carpet and just put down some cheap vinyl roll or something like that. BUT the floor is very very uneven (there is even 3/4 inch deep break in one of the floorboards.

So my question is (without literally replacing the floorboards. Is there simple way to make the surface level so I can put some tiles or flooring on top of it to make it look good?

thanks very much for any advice on this.

 

[dazlight]

Out some 6mm plywood ontop of the floorboards ring nailed or screwed every 6" , 4" on the perimeter.
Then prime and use a smoothing compound fibre reinforced.