I have forgotten how MOA works.

Lets say I zero my 7mm in at 100 yards, and it is shooting 2.5 inches low at 200 yards. My scope has 1/4" MOA per click at 100 yards (one of my scopes says 1/4" MOA at 100, the other just says 1/4" @ 100 yards).

So If I want to shoot at 200 yards, I just click it up 10 clicks correct ? Or is there more to it than that ?

If your scope adjustments are 1/4 MOA, that is roughly 1/4" at 100 yards, 1/2" at 200 yards, etc... To move the point of impact 2.5" at 200 yards, then each click effectively [should] move the point of impact 1/2" at 200 yards, so it would take 5 "clicks".

Make sure you test this at the range. I've found some slop in the adjustments of different makes of scopes. Make the adjustment, then confirm at the range before taking it for the gospel.

Thanks. My scope is a Simmons 3-9x50 right now, it came with the rifle. Id like to change to a different brand later. There is a 3-9x40 Trijicon in the shop at work at that I drool over...lol

As Alyeska states, there is a bit of fudge factor in scope to scope adjustments.

Also, the exact ballistics are going to depend on the particular load you are shooting. Again as suggested, do shoot at the 200 yd mark and make adjustments that are for your particular scope and load. Mileage will vary.