Hi, I'm Charlie Kasov, and this is how to use approximation to find the greatest fraction. Now to use approximation, let's pick up two examples. We have 5 over 29 and we have 7 over 34. So to figure out which one is bigger using approximation, we're going to figure out our reference points. Now 5 over 29 that's kind of close to 5 over 30, it's a little bigger than 5 over 30 but 5 over 30 is like 1 over 6 and 1 over 6 is .16. This is a worthwhile reference point to remember, 7 over 34 is a little bigger than 7 over 35 which is like 1/5th which is .2. So if we have a little bigger than .2, that's definitely going to be bigger than a little bigger than .16. So that's how you use approximation to find the greatest fraction.