September 8, 2009
No CommentsHow to Solve Addition Problems with Fractions
Description
This video is a tutorial on how to add fractions that have different denominators. Several examples are provided in the video and all steps are laid out in an organized manner.
Overview
Adding fractions is not too complicated, but can sometimes be a bit of a problem if the fractions have different denominators. If the fractions have the same denominators then it is easy to add – you are only doing one problem.
Example: (a/b) + (c/b) = (a + c) / b
However, this method only works if you have both denominators set equal to each other. So if you are given fractions with different denominators, you must make them the same. You do this by finding the LCD – the Least Common Denominator. The LCD would be a multiple of both 4 and 6, and it is wisest to go with the lowest number you can find that fits that description. If you are working with small numbers, sometimes the best way is to simply multiply them together, and the number you get would be your LCD, and therefore the number you would use in your denominator. Now, when the numbers in the denominator change you must also change the number in the numerator. You do this by multiplication – whatever you do to the top must be done to the bottom.
Example: (1/2) + (2/3)
The LCD w0uld be 6, because 2 * 3 = 6.
(1/2) + (2/3) = [(1 * 3) / (2 * 3)] + [(2 * 2) / (3 * 2)] = (3/6) + (4/6)
Now you can solve this problem like a normal fraction addition problem.
