units digit: 5 + 0 = 5
tens digit: A + 5 = F
hundreds digit: 1 + D = E
thousands digit: F + B = 1A, so keep the A and carry the 1
ten-thousands digit: 4 + 1 (carried from the thousands digit) = 5
So your answer: 4F1A5 + BD50 = 5AEF5. Both the answer you were given and your answer are wrong.