0
mulitply the denominators you are working with.
ex. 4/5 + 2/3
5 x 3=15
15 is the common denominator.
Now, we multiply the numerators by the old denominators
4 x 3 = 12
2 x 5 = 10
now add them
12 + 10 = 22
put it on the denominator
22/15, or 1 7/15
It's the same as finding the LCM.
Example: 5/30 and 6/42
Factor them.
2 x 3 x 5 = 30
2 x 3 x 7 = 42
Combine the factors, eliminating duplicates.
2 x 3 x 5 x 7 = 210, the LCM
5/30 = 35/210 6/42 = 30/210
Now you can add them.
By definition you write the multiples of each and find the one that is in both lists. the one that is always in both lists is the product of the denominators. That might give you one that is very large. That is why the least common multiple of the two denominators is the best to use.
Prime factor each denominator.
Choose each factor that was used the most. and multiply them,
5/18 + 7/27
18=2x3x3
27=3x3x3
common denominator or LCM=2x3x3x3 or 54
Wiki User
∙ 7y ago
Add your answer:
Earn +20 pts
How do you find the common denominator of 3 fractions?
Pick two of the fractions and find the Least Common Multiple of those two denominators. Then take that number, and find the Least Common Multiple between that and the third denominator. This number will be the Least Common Denominator between the three fractions.If you don't care to find the Least common denominator, then just take the three denominators, and multiply them together.
Find the least common denominator?
The way that you can find the least common denominator is by first multiplying the 2 bottom numbers and whatever the product is that is your common denominator. to find the smallest one, you have to keep dividing it till it is in counting order or there is an odd number.
What is the common denominator of 56 and 7?
A common denominator is 7.A common denominator is 7.A common denominator is 7.A common denominator is 7.
Why do you have to find a common denominator?
Addition or subtraction of fractions require "like" fractions: that is, fractions with the same denominator.
Why do you think it is important to know how to find the common denominator of two rational polynomials?
You need to find the common denominator in order to add or subtract them. You can only add or subtract "like things" and by finding a common denominator you make both rational expressions into things that can be added or subtracted.
How do you keep the denominator the same?
you find the common denominator
Find a common denominator for the pair of fractions. Then, write equivalent fractions with the common denominator?
Find google
Is it always necessary to find the least common denominator to compare the sizes of fractions?
When comparing fractions you must find a common denominator; by finding the least common denominator it will keep the numbers (numerators and denominator) smaller .
How do you add improper fractions if the denominator can't multiply into the other denominator?
You Ned to find a larger common denominator or multiply the denominators to gain a common denominator.
What is the least common denominator of 9?
You need at least two numbers to find a common denominator.
Where is a denominator used?
Many places, but a common one is in adding fractions where we find a common denominator.
What is the common denominator for 1734 and 15?
You can always find a common denominator by multiplying the denominators together.
Do you have to find the common denominator when you multiply?
No.
What goes into 4 and 7 to find a common denominator?
To find a common denominator, it's what 4 and 7 go into, and that's 28.
Does NINETY have a common denominator?
You need at least two numbers to find something in common. 90 can be a common denominator of other numbers, but it can't have a common denominator all by itself.
Do you have to find the lcd when comparing them or can you use any common denominator?
For the sake of comparison, any common denominator will do.
What is the largest common denominator of 20 and 15?
The is no "largest" common denominator. For any denominator you find, we can multiply it by a natural number and come up with a larger one. Do you mean LEAST COMMON DENOMINATOR?
