How to get the + and - buttons back in Acrobat Pro? (Different menus)

Hi, for some reasons I have lost the buttons + and - to zoom in and out in a document.

Machine A:

This is what I have on another machine:

Machine B :

In red the missing buttons.

Both machines are running the same version:

Machine A :

Machine B :

I have looked everywhere up and down in the settings and inthe user documentation, I can't seem to figure out what to do.

More intestingly, in the submenus, there are not the same!

How come?

Machine A :

Machine B :

Can someone explain me what's going on and what to do to get the same settings on Machine A as in Machine B.

Thanks,

Alex