This document introduces how to add fractions. It first reviews what fractions are, with a fraction defined as a way to express decimals using a numerator and denominator. It then explains the two key steps to adding fractions: 1) finding a common denominator by listing the multiples of each denominator and finding a common multiple, and 2) adding the numerators and keeping the denominator the same. An example of each step is provided to illustrate how to add 1/12 + 1/3 by first converting them to a common denominator of 12 and then adding the numerators.

1. Intro to Adding Fractions
By Miss Bright

2. What are fractions? (Review)
Fractions are a way to express
decimals
For example, .25 could also be
expressed as
1
4
, which is the same
thing as 1 divided by 4, which = .25

3. Numerator and Denominator (Review)
The NUMERATOR is the number on top
The DENOMINATOR is the number on
the bottom (denominator, down)
1
4

Numerator
Denominator

4. Adding Fractions (New)
STEP 1- Common Denominator
 To add or subtract fractions, you must have a
common denominator between the fractions in
question. In other words, each fraction has to
have the same denominator.
 Example:
1
2
+
1
4
=
2
4
+
1
4

5. Adding Fractions
STEP 1 Cont.
 To find a common denominator, you must use a trial and error
method, by listing the multiples of each denominator and trying
to find a common multiple.
Example:
1
12
1
3
+
=?
12- 12, 24, 36, etc.
3- 3, 6, 9, 12, 15, etc.
Here, the
common
multiple is 12

6. Example:
1
12
+
1
3
=? (Common multiple=12)
1
12
1푥4
3푥4
+
=
1
12
+
4
12

7. Adding Fractions
STEP 2- Add Numerators
After finding the common denominator, you
simply add the numerators together and keep
the denominator the same.
1
1푥4
1
4
ퟓ
+
=
+
=
12
3푥4
12
12
ퟏퟐ