How do I make sure my objects are always touching the grid floor? I want to use the grid as an imaginary floor.

Is there a mathematical operation to make sure that no matter the length of the object that the bottom of the object is always touching the grid?

Apparently the grid is on 0,0,0 xyz coordinates. If I place my object on the same coordinates it just slashes my object in half. I don't want that. I want the bottom to be on that coordinate.





HA HA! I was going ask this but I think I'm on to it.

What I did is I've gone to edit mode, chose to only select vertex points, selected a bottom vertex point. Copied the Z axis location which was -3.22222 then, I've chosen to select the whole object with A, and just turned that - into a + for the z axis of the whole object and voila we've got a winner.

Someone tell me if this is the correct way or if there's a different way.
There are different ways. If your object has a bottom face that is supposed to touch the plane on z = 0, you select that face in edit mode, call shift+s, cursor to selection. 
Then switch to object mode and change your object's origin by selecting origin to 3D cursor, as shown here:



Then, still in object mode, you can move your object to z = 0 by entering the value directly into the coordinates box.