Lesson 8
Adding Fractions and Mixed Numbers
 

Very Important

You can add or subtract  fractions only when they have the same denominator.

  • Example: You can directly add 1/5 + 3/5 because they have the same denominator.
  • Example: You cannot directly add 1/2 + 1/4 until you adjust them to have the same denominator.

The fact that you can add and subtract fractions when they have a common denominator explains why these operations are often more complicated than multiplying and dividing fractionsthere is that additional step of reworking the fractions so they have the same denominators.

The fact that you can add and subtract fractions only when they have a common denominator explains why these operations are often more complicated than multiplying and dividing fractionsthere is that additional step of reworking the fractions so they have the same denominators.


Topic 1
Adding and Subtracting Fractions: Common Denominators

 

Procedure

To add fractions that have a common, or same, denominator:

  1. Add the numerators to get the numerator for the sum.
  2. Assign the common denominator to the sum.
  3. Reduce or simplify the result as necessary,

Use these interactive examples and exercises to test and strengthen your understanding and build your skills.

 

Procedure

To subtract fractions that have a common, or same, denominator:

  1. Subtract the numerators to get the numerator of the difference.
  2. Assign the common denominator to the difference.
  3. Reduce or simplify the result as necessary.

Use these interactive examples and exercises to test and strengthen your understanding and build your skills.

If you are having any trouble understanding the content of this lesson, you will benefit from a more detailed tutorial on the subject.


Topic 2
Adding and Subtracting Fractions Having Unlike Denominators

 

Procedure

To add fractions that do not have a common denominator:

  1. Find a common denominator for the fractions.
  2. Expand the fractions to have the common denominator
  3. Add the fractions
  4. Reduce or simplify as necessary

Use these interactive examples and exercises to test and strengthen your understanding and build your skills.

If you are having any trouble understanding how to add fractions that have unlike denominators, you will benefit from a more detailed tutorial on the subject.

 

Procedure

To subtract fractions that do not have a common denominator:

  1. Find a common denominator for the fractions.
  2. Expand the fractions to have the common denominator
  3. Subtract the fractions
  4. Reduce or simplify as necessary

Use these interactive examples and exercises to test and strengthen your understanding and build your skills.

If you are having any trouble understanding how to add fractions that have unlike denominators, you will benefit from a more detailed tutorial on the subject.