In order to add fractions you need to change the denominators to make sure they are the same. Then, all you have to do is add the two numerators like normal and keep the denominator the same.
Hope this helps!!!! :D
Check the picture below.
notice that the triangle ADH, since the segment AL is an angle bisector, meaning it cuts the angle A in two equal halves, then the triangle ADH is only using half of A.