1. Working with Fractions
Nina Kennedy

2. Content Area: Mathematics Grade Level: 4th Summary: The purpose of this instructional PowerPoint is to help students understand the basic functions of fractions. Learning Objective: At the end of this lesson, given equations to evaluate, the student will be able to add and subtract fractions with both alike and different denominators with 100% accuracy. Content Standard: Understand adding and subtracting of fractions. Accomplishment: Identify and analyze the numerator and denominator of fractions.

3. Understanding Fractions
A simple fraction is made up of two numbers:
The top number is called the NUMERATOR and the bottom number is called the DENOMINATOR. 3 4
In this fraction the number 3 is the numerator and
the number 4 is the denominator.
The DENOMINATOR represents how many equal pieces something has been
divided into. In the fraction above, the 4 means that there are 4 equal pieces that
make up a whole.
The NUMERATOR represents how many of those pieces are still present. In the
fraction above, the 3 means that there are 3 out of a total 4.

4. A fraction means division.3 4
Means 3 4
Any whole number represented as a fraction is simply written
over the number 1. For example. 3 1 -4 1 3=
-4=

5. Which of the following fractions represents how many pieces are left?
The correct answer would be 5/9 because there are 5 pieces remaining out of 9 total.
*The fraction 4/9 represents how many of the pieces are missing from the total 9.

6. Adding and Subtracting Fractions with the same Denominators
It is easy to add fractions as long as they have the exact same denominator. You just simply add the numerators together and leave the denominator the same. For example: 2 4 1 4
2+1 4 3 4 + = =
The same steps are taken when you subtract fractions. As long as the denominators are the same you just subtract the numerators.
For example: 7 9 2 9
7-2 9 5 9 - = =

7. Adding and Subtracting Fractions with different Denominators
When two fractions have different denominators, we must rewrite them with a common denominator in order to add or subtract them.
6 is a common multiple of 2 and 3. 1 2 1 3 +
Change fraction #1 to an equivalent fraction with a denominator of 6, then multiply top and bottom number by 3 1 2
x 3 3 6 =
x 3
Change fraction #2 to an equivalent fraction with the same denominator of 6 – multiply top and bottom by 2. 1 3
x 2 2 6 =
x 2

8. New fractions with common denominator
Now that both fractions have the exact same denominator, we are ready to add them together. 2 6 3 6
2+3 6 5 6 + = =
When subtracting fractions with different denominators you would use the same
process to make both of them the same. Once you have done so you can subtract the
Numerators and keep the denominator. For instance: 5 6 2 3 5 6 4 6
5-4 6 1 6 - = = =
New fractions with common denominator

9. Now that we understand simple fraction and how to add or subtract them, lets practice.
Directions: Use what you have learned in this lesson to solve the following problems. You may work with another student to compare answers. You have 3 minutes.
2 + 1
3 6
3 - 1
4 2

10. Now, let’s check our work. Your answers should look similar to this: 1

11. STOP
This concludes the lesson on working with fractions. Each student should be able to understand the concept of adding and subtracting fractions with both alike and different denominators. Each student should also be able to recognize a simple fraction and understand the difference between the numerator and the denominator.