# Why do you have to find a common denominator?

## Why do you have to find a common denominator?

In order to add or subtract one fraction from another, they must have a common denominator, or the same denominator. That’s because it’s impossible to add two fractions that have a different number of parts.

Why is it necessary for fractions to have the same denominator in order to add or subtract them?

The real reason is due to the definition of the fraction itself, which is a representation of parts of a total which must be the same size. When you add or subtract fractions, you can’t express the result as a fraction if you do not divide the total into equal parts.

When adding fractions, why don’t you add the denominators? A denominator indicates how many equal pieces make one unit. If you add the denominators when adding fractions, the new denominator won’t describe how many equal pieces are in one unit.

Can you add fractions with the same denominator?

Adding fractions together when they have a common denominator is easy to do, because you can just add all the numerators together! The new fraction will use the same original denominator, so all you have to worry about is adding the numbers above the line.

#### How do you explain a common denominator to a child?

When two or more fractions have the same denominator (the bottom number). We can add and subtract fractions only when they have a common denominator. To get common denominators we can multiply both top and bottom of a fraction by the same amount.

When adding or subtracting fractions you must have a denominator?

What you’ll note is that the numerators are all different, while the denominators are all the same (16). When adding or subtracting fractions, the denominators must be the same. We refer to this as having a common denominator. So, in order to get the answer to the above question, you just add all the numerators.

## What do you need in order to add fractions?

In order to add or subtract, fractions must have common denominators. To add fractions, if the denominators are the same, we simply add the numerators and keep the same denominators. e.g. Since the denominators are common, simply add the numerators.

What is a denominator in fractions?

Definition of denominator 1 mathematics : the part of a fraction that is below the line and that functions as the divisor of the numerator.

### What is the most important thing to remember when adding or subtracting fractions?

common denominator
The most important thing to remember when adding or subtracting fractions is that we must have a common denominator. When the denominators are the same, all you have to do is add or subtract the numerators and keep the denominator the same.

How do u add fractions with the same denominator?

To add fractions with like denominators, add the numerators , and write the sum over the denominator. Example : Find 49+39 . Since the denominators are the same, add the numerators.

#### What is the easiest way to add fractions?

An easy way to add with fractions is to use oil and water. If the denominators of the fraction are the same, you can just measure out the fractions. Make one fraction water and the other fraction oil. Pour them, one at a time, into a separate measuring container.

What are the steps in adding fractions?

To Add Fractions there are Three Simple Steps: Step 1: Make sure the bottom numbers (the denominators) are the same Step 2: Add the top numbers (the numerators), put that answer over the denominator Step 3: Simplify the fraction (if needed)

## How do you calculate addition fractions?

To calculate fractions by adding or subtracting, start by finding a common denominator of the two numbers. Simply multiply the fraction by the denominator of the other fraction to make the denominators the same. For example, to find a common denominator for 1/3 + 2/5, multiply the 1 and 3 by 5 and multiply the 2 and 5 by 3 to get 5/15 + 6/15.

What are the rules of adding and subtracting fractions?

One important key rule for fractions is : Add or subtract the numerator, don’t add or subtract the denominator. The other important rule is: You can always regroup the whole number when you subtract fractions. The other rule is: When you add and subtract fractions, it could be also be known as decimals.