1. Title of Notes: Common Denominators
Pg. 18 RS

2. 5 6 What is a Denominator? The bottom part of the fraction
represents the total parts of the
whole 5 6

3. The Numerator
The top part of the Fraction represents the part that you have 5 6

4. What is a common denominator?
Common denominators are the possible ways that fractions can be used to add or subtract unlike numbers
These fractions can only be Added or Subtracted by finding a common language (Common Denominator) or
Common multiple

5. Find common denominator4
2 x x 4 2 + = = 3 5
3 x 5 22 = 15 15

6. We multiplied each fraction by the denominator of the other
We multiplied each fraction by the denominator of the other. Let's use letters instead of numbers to show it:
This method might be a bit easier at first, but the common denominator you determine might not be the least common denominator. What this means is that, at the end of the addition or subtraction problem, you will have to reduce your fraction to its simplest form.

7. And because they now have the same denominator, we can add them:
This method might be a bit easier at first, but the common denominator you determine might not be the least common denominator. What this means is that, at the end of the addition or subtraction problem, you will have to reduce your fraction to its simplest form.

8. Finding the Least common denominator13 1 2 + = 3 7 21 7
2 x 3
1 x 7 6 = =
3 x 7 21
7 x 3 21
Find the multiples of each denominator
The multiples of 3 are: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30…
The multiples of 7 are: 7, 14, 21, 28, 35, 42…