Number- Addition and Subtraction of fractions with the same denominator

Topic: Addition and Subtraction of fractions

Addition of fractions with the same denominator

To add fractions with the same denominator the following steps are important to follow:

• 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)

REMEMBER: We DO NOT add denominators

Look at the following example:

Let’s look at the following video

Subtracting fractions with the same denominator

In order to subtract fractions with the same denominator properly we have to consider the
following steps:

• Subtract the numerator and it will give us the answer.

• Simplify the fraction, if required.

Example- Subtract from3/15 from12/15.

Solution: As both, the fractions are like fractions

∴ 12/15 – 3/15 = 12 – 3/15 = 9/15

As 9/15 can be simplified, ∴ the final answer is3/5.

Below are the steps to subtract unlike fractions:

• Find the least common multiple (LCM) of the denominators.
• Change the denominator to the LCM by multiplying the numerator and the denominator
  by the same number.
• Once the fractions have the same denominators, subtract the numerators of the
  fractions.
• The difference between the numerator and the LCM will be the numerator and the
  denominator of the answer respectively.
• Simplify the fraction, if required.
• For instance:

   

WHAT IS A LCM?

Finding least common multiple

 Examples

Subtract: 8/10 – 3/10

 Subtract the numerators, then keep the same denominator.

Use the number line to check your answer.

Notice the answer is the same.

Let’s look at the video below