You may change the two given hours into an improper fraction or you can have it in mixed..
Let's have it done first in mixed number
2  \frac{1}{3} + 2  \frac{1}{2}
since this is addition, you may first add the two whole numbers
having it as 
2  \frac{1}{2}
   4 and  \frac{1}{3} +  \frac{1}{2}
for the fractions 1/3 and 1/2, find first the LCD which in this case is 6
 \frac{1}{3} +  \frac{1}{2}  =  \frac{1(2) +1(3)}{6}
                                        =  \frac{5}{6}
therefore your answer will be 4  \frac{5}{6}

If we do it by changing it into improper fraction, we'll have it as:
2  \frac{1}{3}  =  \frac{7}{3}
2  \frac{1}{2} =  \frac{5}{2}
still find the LCD
 \frac{7}{3} +  \frac{5}{2}  =  \frac{7(2) +5(3)}{6}
                                  = \frac{14 + 15}{6}
Converting it into a mixed number you'll have:
4  \frac{5}{6}