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To add fraction with different denominators, you want to move both fractions to a common denominator. You can do this by multiplying each fraction by the a fraction whose numerator and denominator is the same as the opposing fractions denominator.
Example:
7 / 8 + 1 / 2
Multiply each fraction by the other fractions denominator over itself. This will work without changing the value because x / x = 1.
(7 / 8 ) * ( 2 / 2 ) + ( 1 / 2 ) * ( 8 / 8)
Simplify.
14 /16 + 8 / 16
Now just add the numerators together.
24 / 16
Simplify
3 / 2 or 1 1/2
You can also use any other numbers that will get your denominators to the same place. Remember, x / x = 1. And multiplying by 1 doesn't effect the value of the fraction.
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When you add or subtract fractions with unlike denominators why do you have to find LCM?
Because to add fractions, the denominators must be equal.
How do you add three fractions without the same denominators?
When you want to add fractions that have different denominators, you have to convert them into fractions that do have the same denominators. So for example, how much is a half plus a third? Both of these can be converted into sixths, so one half equals three sixths, and one third equals two sixths. Three sixths plus two sixths equals five sixths. That's the answer. If you have three fractions with different denominators, the procedure is the same. Convert all three into fractions with the same denominators, then add them.
How would you add or subtract fractions with like denominators?
The same way you would add or subtract whole numbers, leaving the denominators alone.
How does using fraction strips with like denominators make it possible to add fractions with unlike denominators?
because they are the same number
Explain why you cannot add fractions with unlike denominators?
You can totally add fractions with unlike denominators. You have to first find the LCD (least common denominator) to make them the same denomintars. And then you can just simply add them. What you cannot do is add fractions with unlike denominators without changing them to fractions with like denominators. The reason being that you would be attempting to add fractions that are different sizes. 1/2 is not the same size as 1/3, so it would be like trying to add apples and oranges. You have to change them to a common size and that is the reason you have to find the least common denominator first. While you cannot add 1/2 and 1/3, you can add 3/6 and 2/6.
