Best Answer

Fractions can only be added or subtracted if the denominators are the same.

If the denominators are different, then the fractions need to be made into equivalent fractions with the same denominator.

The new denominator can be found simply by multiplying the denominators together, but this can lead to some large fractions with which to work. A better new denominator is the lowest common multiple of (all the) denominators.

(Once the new denominator is found, the fractions' new numerators are found by multiplying their current numerator by the new denominator divided by their current denominator to make their equivalent fractions with the new denominator.)

Once all the fractions are converted into equivalent fractions with the new denominator then the fractions can be added or subtracted, with the result being simplified (if possible).

User Avatar

Wiki User

โˆ™ 2014-08-22 09:53:00
This answer is:
User Avatar
Study guides


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

See all cards
1982 Reviews

Add your answer:

Earn +20 pts
Q: Adding and subtracting unlike denominators
Write your answer...
Still have questions?
magnify glass
Related questions

What is the definition of adding and subtracting fractions with unlike denominators?

What is the definition of Adding and Subtracting Like Fractions

Fractions Have The Same Denominators?

Not always but they need to have the same denominators when adding or subtracting them.

How is the least common multiple used when adding and subtracting fractions?

When adding and subtracting unlike fractions, find the LCM of the denominators and convert them to it. In this case, it's called the least common denominator, but it's the same process.

How are adding fractions different?

When adding or subtracting fractions their denominators must be the same

What are the rules for adding fractions?

Ensure that the denominators are the same when adding or subtracting fractions.

What did you learn from adding and subtracting fractions?

I learned to always change the denominators before adding or subtracting the numerators. You must always have a common denominator before adding or subtracting.

How would you find the LCD when adding or subtracting rational expressions with different denominators?


Why do you have to have a common denominator?

A common denominator is needed when adding or subtracting fractions of different denominators.

What is the most important thing about adding and subtracting fractions?

Making sure the denominators are the same.

When adding or subtracting fractions do you have to have the numerator the same or denominator?

The denominators must be the same, the numerators can be different.

What is the first thing you should look for when adding or subtracting fractions or mixed numbers?

common denominators.

Can you multiply fractions that have a different demonminator?

Yes. When multiplying and dividing fractions your denominators do not have to be the same. The denominators only haveto be the same if you are subtracting or adding them.

People also asked