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Because to add fractions, the denominators must be equal.

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Q: When you add or subtract fractions with unlike denominators why do you have to find LCM?
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How do you subtract Fractions with models unlike denominators?

The denominators need to be the same for subtraction. Find the Least Common Denominator for both items and then subtract.


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.


What way is subracting fractions with unlike denominators like adding fractions with unlike denominators?

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.


How do you add and subtract by fractions?

If the fractions have the same denominator, add and subtract the numerators as if the denominators weren't there and put the result over that denominator. Reduce if possible. If the fractions have different denominators, find the LCM of the denominators and convert the fractions to equivalent fractions with like denominators. Then add and subtract the numerators as if the denominators weren't there and put the result over that denominator. Reduce if possible.


How is finding the LCM revelant when adding and subtracting fractions?

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


How do you minnous fractions?

Subtracting fractions is similar to adding fractions. If the fractions have the same denominator, you subtract the numerators. If the fractions have different denominators, you have to convert to a common denominator first.Subtracting fractions is similar to adding fractions. If the fractions have the same denominator, you subtract the numerators. If the fractions have different denominators, you have to convert to a common denominator first.Subtracting fractions is similar to adding fractions. If the fractions have the same denominator, you subtract the numerators. If the fractions have different denominators, you have to convert to a common denominator first.Subtracting fractions is similar to adding fractions. If the fractions have the same denominator, you subtract the numerators. If the fractions have different denominators, you have to convert to a common denominator first.


How do you find the difference of two fractions with the same denominator?

Subtract as if there were no denominators.


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.


When adding fractions with unlike denominators it is most helpful if the fractions are renamed using the?

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.


Why do you need to find a common denominator before you can add or subtract fractions with unlike denominators?

Because if you skip that step . . . -- you'll need to invent your own method for adding fractions with different denominators, because every method you'll ever be taught or find on your own requires common denominators, and -- the answer you get will be wrong.


Explain how comparing fractions with like denominators differs from comparing fractions with unlike denominators?

Because when you compare fractions with the same denominators, you do not have to find the least common denominator (LCM or LCD).


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.