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

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.

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

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.

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.

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.

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.

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.

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.

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.

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

To add and subtract unlike fractions, find the LCM of the denominators and convert them to equivalent like fractions. You don't have to do anything to fractions to multiply them, but you may need to reduce one after multiplying. To do that, find the GCF of the numerator and the denominator and divide both of them by it. If the GCF is 1, the fraction is in its simplest form.

In order to add or subtract one fraction from another, they must have a common denominator, or the same denominator. That's because it's impossible to add two fractions that have a different number of parts.

Finding the prime factorizations of the denominators will help you find the least common denominator. Converting to equivalent fractions with like denominators will allow you to subtract them successfully.

Find the lowest common multiple of the denominators and adjust the fractions accordingly

multiply the two denominators

You first find equivalent fractions whose denominators are a common multiple of the different denominators. Teachers like you to use the least common denominator: that is not necessary although it can result in your working with smaller numbers and so make things easier.

A common denominator. The best way is to find the LCM (Lowest Common Multiple) of all the denominators - the smallest number into which all the denominators will divide. (The easiest way to do this is to multiply all the different denominators together. Once this common denominator has been found, convert all the fractions into equivalent fractions with this new denominator.

It means find the LCM of the denominators. In order to add and subtract fractions with unlike denominators, it is necessary to convert them to equivalent fractions with a common denominator. Example: 1/4 + 1/6 The LCM of 4 and 6 is 12. 1/4 = 3/12 1/6 = 2/12

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.

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.

Knowing the LCM of the denominators will help you to find a least common denominator of unlike fractions, which will allow you to add and subtract them successfully. Knowing the GCF and LCM will not help you in multiplying them, but knowing the GCF of the numerator and denominator of a fraction will help you reduce it if necessary.

Subtract their numerators providing that they both have the same denominators.

When adding unlike fractions, find the LCM of the denominators and convert them to it.

When adding unlike fractions, find the LCM of the denominators and convert them to it.