You find the least common multiple of the denominators [or least common denominator].
Basically, the Least Common Denominator equals the two denominators multiplied together and then divided by any common prime factors. It is easy to see that the numbers 2 and 3 have a common denominator of 6. But the number 4 and 6 do not have a least common denominator of 24, because both numbers are factors of the number 12 (the least number).
Example : add 1/2 and 1/3 -- multiply the numerator and denominator by the same number : (1/2) x (3/3) = 3/6 and (1/3) x (2/2) = 2/6. We are multiplying them by a fraction equal to 1.
Now you can add 3/6 + 2/6 = 5/6
Example : subtract 1/6 from 3/4 -- multiply 1/6 by 2/2 and multiply 3/4 by 3/3
1/6 = 2/12 and 3/4 = 9/12
so 3/4 - 1/6 equals 9/12 - 2/12 = 7/12
If the result is a reducible fraction, reduce it.
Because to add fractions, the denominators must be equal.
The same way you would add or subtract whole numbers, leaving the denominators alone.
The denominators must be the same before you can add or subtract fractions.
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.
When you add or subtract fractions with like denominators, you just add or subtract the numerators and put them over the same denominator. For example, 3/5 - 2/5 = (3 - 2)/5 = 1/5
Because you can't add or subtract fractions that have different denominators. Making them like fractions, by multiplying so the denominators are the same, you can add and/or subtract them.
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.
You cannot add or subtract fractions with different denominators. If the denominators are different then you need to work with equivalent fractions.
In fractions, you can NEVER add or subtract
Because to add fractions, the denominators must be equal.
Possible reasons: To add or subtract fractions, To compare fractions with different denominators.
YOU JUST CANT....go on you try it
The same way you would add or subtract whole numbers, leaving the denominators alone.
Whether the denominators are common or not.
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.
The LCM is used to help you add or subtract fractions with different denominators.
When you are trying to add or subtract fractions with different denominators.