Step 1 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, too. They get multiplied by the other term's denominator. So we multiply 7 by 3, and get 21. Then we multiply 1 by 8, and get 8. Next we give both terms new denominators 8 × 3 = 24. So now our fractions look like this: 21/24−8/24
Step 2 Since our denominators match, we can subtract the numerators. 21 − 8 = 13 So the answer is: 13/24
