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To add or subtract fractions the denominators must be the same - then the numerators are added or subtracted with the denominator being kept the same.

When adding or subtracting fractions with different denominators, the fractions must first be converted into equivalent fractions with the same denominator and then the (new) numerators can be added or subtracted as required.

For the denominator for these equivalent fractions, the original denominators can all be multiplied together, but this can lead to having to work with very large numbers; a better choice for the denominator is the smallest number that all the denominators divide into, their Least Common Multiple (LCM) - this is is then used as the denominator for the equivalent fractions and is called the Least Common Denominator (LCD) of the fractions.

First you find the LCD okay??? Then you have to add or subtract. What they mean by that is that once you've found your lcd add or subtract..xx hope i helped :)

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โˆ™ 2012-06-04 04:07:33
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Q: Find the LCD then add or subtract?
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Related questions

How the LCD of two or more fractions could be of use?

Once you find the LCD, convert the fractions to their equivalents and then you can add and/or subtract them correctly.

Least common denominator find the LCD add or subtract?

Neither. Factorise and then multiply a subset of factors.

How do you add mixed numbers?

Find theLeast Common Denominator (LCD)Find the equivalent fractions.Add or subtract the fractions and add or subtract the whole numbers.Write your answer in lowest terms.

How do you subtart fractions?

subtract? Find a common denominator (LCD is preferred). Convert each fraction to an equivalent fraction with the LCD. Add numerators, keep LCD as new denominator. Reduce the fraction.

Do you add or subtract to find the range?

Subtract the largest data with lowest data

Why are least common denominators important?

In order to subtract or add fractions the denominators must be the same and that's why the LCD must be found.

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.

Does deposit mean to add or subtract?

deposit = add withdraw = subtract

Why would you want to rename fractions with the LCD?

Possible reasons: To add or subtract fractions, To compare fractions with different denominators.

Does decrease mean to add or subtract?


What happens when you add and subtract energy?

How do you add or subtract energy?

How do know when to subtract and add when doing Pythagorean theorem?

To find the larger side you add the 2 legs together, for the smaller sides you subtract the other 2 legs :)

Does commisson mean add or subtract?

The answer depends on what you know and what you are trying to find.

Why do you need to find the LCM of a fraction?

or else you cannot add or subtract them

What must you find to subtract and add with different denominators?

the new denominator

What is common donominator?

It's something that you find to add and subtract fractions

How do you add and subtract like denominator?

You add or subtract only the numerators

What do you have to add to subtract a rational number?

You have to add the additive inverse. To subtract q, you add -q.

When it says how much add or subtract?

it means to subtract

When and why should you find the LCM?

When you want to add or subtract fractions and need to find a common denominator.

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.

How do you know whether you should add or subtract the value of the two numbers?

By the signs: 2+2(Add) 2-2(Subtract) +=add -=subtract

Can you add or subtract under the radical?

Yes, you can add or subtract under the radical.

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.

Why do you calculate the LCM?

You will need to find the LCM in order to add and subtract fractions.