In this video we will subtract 1/2 - 1/4. First we need to find a common denominator both 1/2 and 1/4. Once we have a common denominator, we can easily subtract the numerators while keeping the denominator the same.
Note that the lowest common multiple (LCM) is also called the lowest common denominator (LCD). You can find the LCM for and by listing all the multiples for 2 and 4. Then you select the lowest number that is the same for both numbers.
If we look at the multiples of 2 and 4, we'll find that both 2 and 4 can be divided evenly into 4. So 4 is the lowest common denominator. We multiply the 1/2 by 2/2 to get 2/4. We can now subtract these fractions to get 1/4, our final answer.
