No worries about asking

MOA is actually 1.047" at 100 yards (1 / 60th of a degree) but in generic terms it is considered 1inch per hundred yards.

***The difference between the two becomes evident when you start increasing the number of MOA and increasing the distance.***

I adjusted my scope from 200 to a 550yard sight in and accidentaly used MOA rather than Inch incraments and I was off by sevearl inches (enough to miss my target totally).

When someone says that the adjusted 24 moa to hit at 850 yards - what they are saying is that from their base "Zero" range (I'll pick 200 yards), they needed to adjust their scope 24 inches per hundred to be able to hit right on at 850. 24 inches per hundrd equals 24 x 8.5 (24 x 850 / 100yards) which is 204 inches at 850 yards. This means that their bullet dropped 204 inches below the crosshair at 850 yards when sighted in at 200 yards. 24 MOA at 850 yards is actually 213.6" of drop.

Many people just say MOA becuase it is easier to say than inches per hundred.