answersLogoWhite

0


Best Answer

Finding a common denominator makes it possible to add two fractions because it allows us to write each fraction as a multiple of a common (usually smaller) fraction.

Subtracting fractions works the same way; find a common denominator so that the fractions involved are in the same terms.

User Avatar

Wiki User

13y ago
This answer is:
User Avatar

Add your answer:

Earn +20 pts
Q: Why do you need like denominators to add and subtract fractions?
Write your answer...
Submit
Still have questions?
magnify glass
imp
Continue Learning about Math & Arithmetic

Why does the equivalent fraction make adding and subtracting fractions easier?

You cannot add or subtract fractions with different denominators. If the denominators are different then you need to work with equivalent fractions.


How do you add and subtract fractions in math?

You need common denominators. Then add or subtract the numerators. If the answer is an improper fraction it is common practice to reduce it to a mixed number.


Why do you need to find a common denominator before you can add or subtract fractions with unlike denominators?

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.


Do you need common denominators when subtracting fractions?

Yes. You need common denominators if you want to:Add fractionsSubtract fractionsCompare fractions ("which is larger?")You do not need common denominators to multiply or divide fractions. Thus, in the case of fractions, multiplication and division is actually easier than addition and subtraction.


Why is it important to learn about equivalent fractions?

Answer: When adding or subtracting fractions with different denominators it is important to change the denominators into the lowest common denominator by using equivalent fractions. Answer: Equivalent fractions are used to: * Simplify fractions. It is sort of inelegant to write the final solution of a problem as 123/246, when you can just as well write it as 1/2. * Add fractions. If two fractions have different denominators, you need to convert them to equivalent fractions that have the same denominator. Only then can you add. * Subtract fractions (same as addition). * Compare fractions, to check which one is larger (same as addition).

Related questions

How do you subtract Fractions with models unlike denominators?

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


How is finding the LCM revelant when adding and subtracting fractions?

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.


Why does the equivalent fraction make adding and subtracting fractions easier?

You cannot add or subtract fractions with different denominators. If the denominators are different then you need to work with equivalent fractions.


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.


When do you need a common denominator?

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


When you are multiplying fractions do you need like denominators?

No.


How do you add and subtract fractions in math?

You need common denominators. Then add or subtract the numerators. If the answer is an improper fraction it is common practice to reduce it to a mixed number.


When adding fractions with like denominators how do you convert?

When adding fractions with like denominators, add the numerators together and put the result over the denominator. Simplify if possible.


How is adding like fractions and adding unlike fractions the same?

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.


What are fraction that have same denominator called?

They are called like fractions.In order to add or subtract fractions you will usually need to convert them to like fractions. Then you simply add or subtract the numerators (as required) to form the numerator of the answer. The same (or common) denominator is the denominator of the answer. You may need to simplify the resulting fraction.


What way is subracting fractions with unlike denominators like adding fractions with unlike denominators?

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.


How do you add and subtract mixed numbers?

SUBTRACTION: You first turn both mixed numbers into improper fractions. If needed, change the denominators into like denominators. Next, subtract the two improper fractions and reduce if necessary. ADDITION: If needed, turn denominators so they are the same number. Next, add and reduce if necessary.