I see that the "ctrl numpad +" and "ctrl numpad -" works but if I select all the mesh with "ctrl numpad +", once all the m...

posted to: Select More or Less
I see that the "ctrl numpad +" and "ctrl numpad -" works but if I select all the mesh with "ctrl numpad +", once all the mesh is selected "ctrl numpad -" doesn't work. So I need tu use A to deselect all. Imagine there are 2 mesh in one scene. How could I diselect with "ctrl numpad -" without deslecting all mesh with A?