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