By Doug Harley

“I Can’t. I simply can’t.”

Fractions are not ready to be added until they have a common denominator.

Response: My Left Side

“I can’t. I simply can’t. Those fractions are not ready to be added.”

Response: My Right Side

“Stop!!! Back away from those fractions. Those fractions are not ready to be added.”

Objective

Without using any notes, you will be able to add and subtract fractions with unlike denominators with 90% accuracy.

Least Common Denominator (LCD)

Given the fractions 1/6 and 3/8, you should be able to calculate that the LCD is 24.

Building up Fractions

Given that the LCD for the fractions 1/6 and 3/8 is 24, you should be able to build up each fraction to obtain an equivalent fraction with the LCD.

1/6 = 4/24 3/8 = 9/24

Adding Fractions with like Denominators

Given two fractions with like denominators, you should be able to calculate the sum of the two fractions.

4/24 + 9/24 = 13/24

Subtracting Fractions with like Denominators

Given two fractions with like denominators, you should be able to calculate the difference of the two fractions.

9/24 - 2/24 = 7/24

Simplifying Fractions

Given a fraction that can be reduce, you should be able to reduce the fraction.

12/15 = 4/5

Adding Fractions with unlike Denominators

Given two fractions with unlike denominators, you should be able to calculate the sum of the two fractions.

3/5 + 2/7 = 31/35

Resources

Waztamann, (2009). I simply can’t. Retrieved from: http://www.youtube.com/watch?v=Wu4onoiOzQw&feature=related