First you get common denominators. 5 1/8 = 5 1/8 and 2 3/4 = 2 6/8. Now subtract. To do this, we have to regroup. We take a whole number away and give it 8/8. So we turns 5 1/8 into 4 9/8. Now we can subtract. 4 9/8 - 2 6/8 = 2 3/8, so your answer is C. I hope this helps.
