FINDING THE LEAST COMMON DENOMINATOR (LCD)
We may add or subtract fractions only if they have a common denominator.
If they do not have a common denominator, they must be converted to a common denominator
before adding or subtracting.
We may not add: 1
yet, because the denominators are
In order to add fractions such as 1
+ 1, we must change the
denominators to make them the
The procedure for making the denominators the same is called finding the least common
The least common denominator is also called the lowest or smallest common denominator.
It is called least or lowest because it is the smallest number that we can use as a common
The smallest number that we can use as a common denominator is called the