9/10. When you have fractions with different denominators, you need to make them a common denominator. So, the only one that has a different denominator is 1/5. To make it 10, we need to multiply the bottom number by 2. Whatever you do the bottom, you must do to the top. So the three numbers become 7/10, 9/10, and our new number, 2/10. Out of these, 9/10 is the biggest.