Okay, I probably sound really stupid to ask this, but my mathmatics teacher last year skipped this unit and I'd like to know this year. If Omar was born in the year 33 B.C., in what year would Omar be 48 years old.

33 BC (before Christ) call that (-33) years (BC) + 48 years = 15 AD.

It's not as hard as you think. If you look at BC as to the LEFT of the number line (negative) then add what you want to be (age 48), you would see that from -33 to 0 = 33 years old for 0 AD. Then 48 -33 = 15 years, so add 15 years to 0 AD = 15AD.