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I can only think to explain this with an example: Consider that 1 foot = 12 inches. So each inch is 1/12 of a foot. If you want to add 2 feet and 3 inches, you would not come up with 2 + 3 = 5. You need to convert so they are some common unit, before adding. so 2 feet = 24 inches (or 24/12 feet), and 3 inches = 3/12 feet. Then you can add them and get 27/12 feet.
Another example. Suppose you have a Pizza that has been sliced into 12 slices, so each piece is 1/12 of the whole. As soon as you open the box, some friends come over and grab some slices, and you notice that 1/2 the pizza has been taken. You go ahead and take 2 slices (2/12). So the question could be how many pieces have been taken (addition), or how many pieces are left (subtraction).
Well if you had counted when your friends were grabbing slices, then you could just subtract the actual slices, so this is what we are doing with fractions. Everything must be in common. So the 1/2 that was taken first must be converted to be in common with the 2/12 that you took. So you could simplify your 2/12 to 1/6, then convert 1/2 to sixths = 3/6. 1/6 + 3/6 = 4/6, which simplifies to 2/3. And 1 - 2/3 = 3/3 -2/3 = 1/3. Then if you want to know how many pieces were taken: (2/3)*12 = 24/3 = 8 slices.
Wiki User
∙ 13y ago
Wiki User
∙ 8y agoTo get the right answer. It's not immediately obvious what the sum of 1/2 and 1/3 is. But if you realize that 1/2 = 3/6 and 1/3 = 2/6, then 1/2 + 1/3 = 3/6 + 2/6 = 5/6
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Adding unlike fractions?
If the denominators are not the same, then you have to use equivalent fractions which do have a common denominator . To do this, you need to find the least common multiple (LCM) of the two denominators. To add fractions with unlike denominators, rename the fractions with a common denominator. Then add and simplify.
How do you add or subtract dissimilar fractions?
You first convert them to similar fractions, i.e., to fractions that have the same denominator.* Step one: find a common denominator.* Step two: convert both fractions to equivalent fractions that have that denominator.
Do you need a common denominator when adding fractions?
Yes, you must convert both fractions to the same denominator to add them. Now... Do the rest of your homework yourself!
How is adding like fractions and adding unlike fractions the same?
If the denominators are not the same, then you have to use equivalent fractions which do have a common denominator . To do this, you need to find the least common multiple (LCM) of the two denominators. To add fractions with unlike denominators, rename the fractions with a common denominator. Then add and simplify.
Addition of fractions?
find a common denominator. Then just add across.
Do you need a common denominator for all fractions before doing the order of operations?
You DO need a common denominator to add, subtract, or compare fractions. You DO NOT need a common denominator to multiply or divide fractions.
What you need to add or subtract fractions?
You need a common denominator in order to add or subtract fractions.
Why do you need a common denominator?
Common Denominator means that the denominators in two (or more) fractions are common, or the same. The common denominator is important because before you can add or subtract fractions, the fractions need to have a common denominator.Sometimes fractions have different denominators, like 2/3 and 3/4. If you want to add or subtract them, they need to have the same denominator. In order to do that, you find a common denominator which is the same thing as a common multiple, only with denominators.
Why do you need a common denominator with fractions?
You can add or subtract fractions only if they are "like" fractions, that is, only if they have the same denominator - unless you know your fractions really well.
Why do you need to use common denominator?
To get the right answer when you add or subtract unlike fractions.
Adding unlike fractions?
If the denominators are not the same, then you have to use equivalent fractions which do have a common denominator . To do this, you need to find the least common multiple (LCM) of the two denominators. To add fractions with unlike denominators, rename the fractions with a common denominator. Then add and simplify.
Why do fractions need a common denominator before you add or subtract?
Because the answers will be wrong when adding or subtracting them if they don't have a common denominator.
Why do you need a common denominator when you add fractions?
Unless you are using a calculator that adds them for you, it is much harder to add fractions with uncommon denominators. Having the same denominator allows you to only have to add the numerators for your answer.
When do you need a common denominator?
The denominators must be the same before you can add or subtract fractions.
How do you add or subtract dissimilar fractions?
You first convert them to similar fractions, i.e., to fractions that have the same denominator.* Step one: find a common denominator.* Step two: convert both fractions to equivalent fractions that have that denominator.
Do you need a common denominator when adding fractions?
Yes, you must convert both fractions to the same denominator to add them. Now... Do the rest of your homework yourself!
Why do fractions need to have a common denominator?
They need a common denominator when you add them. For example, if you want to add 1/2 and 1/3, you need to change the fractions to equivalents that share the same denominator, so you can combine them. 1/2 + 1/3 = 3/6 + 2/6 = 5/6
