answersLogoWhite

0


Best Answer

Because the answers will be wrong when adding or subtracting them if they don't have a common denominator.

User Avatar

Wiki User

โˆ™ 2015-12-03 13:46:52
This answer is:
๐Ÿ™
0
๐Ÿคจ
0
๐Ÿ˜ฎ
0
User Avatar
Study guides

Algebra

20 cards

A polynomial of degree zero is a constant term

The grouping method of factoring can still be used when only some of the terms share a common factor A True B False

The sum or difference of p and q is the of the x-term in the trinomial

A number a power of a variable or a product of the two is a monomial while a polynomial is the of monomials

โžก๏ธ
See all cards

Factoring and Multiples

21 cards

What is the prime factorization of 24

What is the prime factorization of 54

What is the prime factorization of 64

What is the prime factorization of 34

โžก๏ธ
See all cards

Factoring and Multiples

22 cards

What are the particles of matter

Particles of matter move slower as the matter is heated

What are the common factors of 32 and 54

Factors of 325

โžก๏ธ
See all cards

Add your answer:

Earn +20 pts
Q: Why do fractions need a common denominator before you add or subtract?
Write your answer...
Submit
Related questions

Do you need a common denominator for all fractions before doing the order of operations?

You DO need a common denominator to add, subtract, or compare fractions. You DO NOT need a common denominator to multiply or divide fractions.


How do you minnous fractions?

To subtract fractions with like denominators, subtract the numerators , and write the difference over the denominator. Example : Find 45โˆ’25 . Since the denominators are the same, subtract the numerators.


Why do you need a common denominator?

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.


How do subtract two fractions with different denominator?

First find the lowest common denominator and then adjust the fractions accordingly before subtracting the numerators


How do you subtract fractions when denominator is different?

By finding the lowest common denominator of the fractions.


When do you need a common denominator?

The denominators must be the same before you can add or subtract fractions.


How do you subtract fractions in simplest form?

You first need to find a common denominator, not necessarily the least common denominator. Next, you rename the fractions according to the common denominator. Only then can you subtract the fractions. After subtraction you should simplify the answer.


What you need to add or subtract fractions?

You need a common denominator in order to add or subtract fractions.


When you subtract fractions do you subtract the denominator?

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


How do you subtract fractions with unequal denominators?

by finding the common denominator of the fractions


Why do fractions need to have a common denominator before add or subtract them?

because it would be diffcult to understand.[you don't add or subtract the demonters]


How do you subtract mixed fractions when they have the same denominator?

The numerator of the answer is the result of subtracting the numerators of the fractions, and the denominator of the fraction is the same as the common denominator.


Do you have to find a common denominator to subtract fractions?

Yes.


How do you add or subtract dissimilar fractions?

You first convert them to similar fractions, i.e., to fractions that have the same denominator.* Step one: find a common denominator.* Step two: convert both fractions to equivalent fractions that have that denominator.


When is a common denominator needed and when is one not needed?

A common denominator is required to add or subtract fractions and not otherwise.


Why do you need a common denominator with fractions?

You can add or subtract fractions only if they are "like" fractions, that is, only if they have the same denominator - unless you know your fractions really well.


Why do fractions need to have common denominator before you add or subtract them simple answer pleas?

So that you only have to add/subtract the numerator which makes it much easier.


How do you subtract mixed number with different denominator?

Convert them to improper fractions with a common denominator.


How do you subtract two fractions?

You have to find a common denominator, multiply them, subtract them and then simplify if you need to.


What do you do when you're going to subtract fractions but the numerator is the same?

Whether the numerators are the same or not, you need to get the denominators to be the same. First, find the least common denominator. Then convert the fractions to equal fractions that use the common denominator. Then you can subtract the fractions by subtracting the numerators. Finally, look for common factors between the numerator and the denominator of the difference in order to put the answer in simplest terms.


What is the process of subtracting fractions?

If the denominators are the same, subtract the numerators. If the denominators are different, convert them to equivalent fractions with a common denominator and subtract the numerators.


How do you subtract mixed fractions with uncommon denominators?

You must first convert the fractions to equivalent improper fractions with 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.


Do you have to have a common denominator when you are adding fractions?

Having a common denominator makes it easier to add or subtract fractions. You can also convert fractions to decimals and then do the addition or subtraction but that is really the same thing as having a common denominator of 10. 100. 1000. etc. Without a common denominator, you would have to mentally make adjustments for the values of fractions. Of course, that is really establishing a common denominator in your head.


Why do you need to use common denominator?

To get the right answer when you add or subtract unlike fractions.