Together they compete led a full half of the work. You can find this out by separating the fractions from the equation, 1/6 and 1/3. In order to add fractions to each other they need to have the same denominator so you need to multiply 1/3 by 2 to get 2/6. Then you simply add 1/6 and 2/6 together and get 3/6. If asked to simplify turn it into 1/2