Well, you can't add it yet because the denominators don't match. We can't subtract two fractions with different denominators. So you need to get a common denominator. To do this, you'll multiply the denominators times each other... but the numerators have to change as well. So, multiply 3 by 8, and get 24.Since 4 is evenly divided by 8, we can multiply just one term to get a common denominator. Multiply 3 by 2, and get 6, then we multiply 4 by 2 and get 8. Since our denominators match, we can add the numerators. So now your answer should be 9/8. Well guess what... IT IS THE ANSWER! You can't reduce it anymore so 9/8 is your answer! Hope this helped!