Larger number = bigger exit diameter or what some try to call constriction at least on the choke packages. Actually the exit diameter of a choke is the very end of the parallel section that on a lot of turkey chokes is 1.5". But you can take a caliper and measure your exit diameter at the muzzle end of the choke. Tighter exit diameters typically will produce more denser tighter patterns, but there is a point that you can get too tight depending on the actual bore of your barrel that typically will range from .723 for Benelli shotguns to around .729 to .731 for Rem and Win/Browning/Moss 500 Invector barrel shotguns and .742 for the newer Browning Invector Plus barrels and Win X2 and X3 shotguns to .775 on the Moss 835 shotguns and the constriction that you are trying to squeeze down with a choke from the barrel dimension which actually determines the actual meaning of constriction by the way. When you get too tight of a choke diameter in the size barrel you are shooting, you can actually be constricting the shot too tight with too small of an exit diameter choke and get holes in your pattern. I would rather stay more open on the exit diameter than to get too tight of choke. Most standard 12GA bores will like chokes from .655 to .675 exit diameters from my findings. And shot sizes will also determine what size choke diameter you may need. Typically the smaller shot will tend to like a little tighter choke and the larger shot will like a more open choke. The Moss 835 will tend to like chokes from .670 to .690 depending on the size shot you select.
