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Q: Why do you need the lowest common denominator for adding but not multiplying fractions?

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Multiplying fractions is quite different from adding them. You just multiply the numberators and the denominators separately. You can find the common denominator if you like, but in the end (after simplifying), you'll get the same result, and the additional work of finding the common denominator and converting the fractions turns out to be unnecessary. Try it out for some fractions!

You basically have to learn separately how to do different things with fractions, including finding a common denominator; converting fractions to a different denominator; simplifying fractions; adding and subtracting fractions; multiplying fractions; dividing fractions.

No.

no

When adding and subtracting unlike fractions, it is necessary to find the LCM of the denominators, called the least common denominator. Once you have found the LCD, you can convert the fractions to equivalent fractions with a common denominator and proceed with the adding and/or subtracting. Finding an LCM will have no effect on multiplying fractions.

No only when adding or subtracting fractions a common denominator is needed

When multiplying fractions, the numerators (top numbers) are multiplied together and put as the numerator over the denominators (bottom numbers) multiplied together.When adding fractions, they must both have the same denominator - the fractions are made into equivalent fractions with a common denominator; then the numerators are added together and put over the same common denominator.In both cases of multiplication and addition, the resulting fractions are reduced to simplest form.

No you do not.

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

They have to have a common denominator

To add fractions, you have to find their common denominator by multiplying the two denominators together and one of the numerators to the others. Then you add just the top numbers together.

A common denominator is needed when adding or subtracting fractions of different denominators.

Just add the fractions, and divide by 2. Before adding, you have to convert to a common denominator; in this case, you can use "4" as the common denominator.Just add the fractions, and divide by 2. Before adding, you have to convert to a common denominator; in this case, you can use "4" as the common denominator.Just add the fractions, and divide by 2. Before adding, you have to convert to a common denominator; in this case, you can use "4" as the common denominator.Just add the fractions, and divide by 2. Before adding, you have to convert to a common denominator; in this case, you can use "4" as the common denominator.

Many places, but a common one is in adding fractions where we find a common denominator.

No, You only need a common denominator when adding or subtracting fractions.

yes

A Common Denominator

Yes.

You need a common denominator for both.

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.

YES.

No, you only need a common denominator when adding or subtracting fractions.

Find a common denominator and proceed.

Common denominator

a common denominator