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Then they have the same units. As a comparison, if you want to add different units of length, for instance meters and centimeters, you have to convert everything to meters (or everything to centimeters), before you add it.

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โˆ™ 2011-12-17 23:06:31
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Q: Why do fractions need a common denominator before you add or subtract them?
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How do you minnous fractions?

To subtract fractions with like denominators, subtract the numerators , and write the difference over the denominator. Example : Find 45โˆ’25 . Since the denominators are the same, subtract the numerators.


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.


How do you subtract fractions when denominator is different?

By finding the lowest common denominator of the fractions.


How do subtract two fractions with different denominator?

First find the lowest common denominator and then adjust the fractions accordingly before subtracting the numerators


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 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.


When do you need a common denominator?

The denominators must be the same before you can add or subtract fractions.


What you need to add or subtract fractions?

You need a common denominator in order to add or subtract fractions.


How do you subtract fractions in simplest form?

You first need to find a common denominator, not necessarily the least common denominator. Next, you rename the fractions according to the common denominator. Only then can you subtract the fractions. After subtraction you should simplify the answer.


How do you subtract fractions with unequal denominators?

by finding the common denominator of the fractions


When you subtract fractions do you subtract the denominator?

No. If the denominators are the same, you subtract the numerators. If the denominators are different you have to find the least common denominator.


Do you have to find a common denominator to subtract fractions?

Yes.


How do you subtract mixed fractions when they have the same denominator?

The numerator of the answer is the result of subtracting the numerators of the fractions, and the denominator of the fraction is the same as the common denominator.


Why do fractions need to have a common denominator before add or subtract them?

because it would be diffcult to understand.[you don't add or subtract the demonters]


When is a common denominator needed and when is one not needed?

A common denominator is required to add or subtract fractions and not otherwise.


How do you subtract mixed number with different denominator?

Convert them to improper fractions with a common denominator.


How do you subtract two fractions?

You have to find a common denominator, multiply them, subtract them and then simplify if you need to.


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.


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.


Why do fractions need to have common denominator before you add or subtract them simple answer pleas?

So that you only have to add/subtract the numerator which makes it much easier.


What is the process of subtracting fractions?

If the denominators are the same, subtract the numerators. If the denominators are different, convert them to equivalent fractions with a common denominator and subtract the numerators.


How do you subtract mixed fractions with uncommon denominators?

You must first convert the fractions to equivalent improper fractions with a common denominator.


What do you do when you're going to subtract fractions but the numerator is the same?

Whether the numerators are the same or not, you need to get the denominators to be the same. First, find the least common denominator. Then convert the fractions to equal fractions that use the common denominator. Then you can subtract the fractions by subtracting the numerators. Finally, look for common factors between the numerator and the denominator of the difference in order to put the answer in simplest terms.


Why do you need to use common denominator?

To get the right answer when you add or subtract unlike fractions.


How are lcm's used in adding or subtracting fractions?

To add and subtract fractions, you need common denominators. To find the common denominator, take the LCM of the denominators you wish to add or subtract.