Transcript EDI NS 2_3 Reducing Fractions

Today we will add and
subtract simple fractions and
mixed numbers and write
them in simplest form.
simple=most basic
We’ve learned how to add and subtract
fractions and mixed numbers.
We know that :
22
4 x 3 = 12
5 x 3 = 15
2 x 5 = 10
- 3 x 5 = 15
2
15
11
22

 55
11
33



7

5
6
7

5
6

Factor

A number that divides
evenly into another.
Factors of 24 are 1,2, 3, 4, 6,
8, 12 and 24.

What are the factors of 9?

Factors of 9 are 1, 3 and 9.
What are the factors of 10?

Factors of 10 are 1, 5 and 10.
What are the factors of 7?

Factors of 7 are 1 and 7.
What are the factors of 56?
Factors of 56 are 1, 2, 4, 7, 8,
14, 28, and 56.

Common Factor
When two numbers have the
same factor it is called a common
factor.
 A common factor of 12 and 6
is 3.

Name a Common Factor of
9 and 27?
1, 3, 9
Name a Common Factor of
4 and 8?
1, 2, 4
Name a Common Factor of
4 and 8?
1, 2, 4
Name a Common Factor of
15 and 30?
1, 3, 5, 15
Name a Common Factor of
12 and 48?
1, 2, 3, 4, 6, 12
Name a Common Factor of
9 and 21?
1, 3, 9,
Name a Common Factor of
10 and 25?
1, 5, 10
Name a Common Factor of
3 and 4?
1
Simplest Form

When the only common
factor of the numerator and
denominator is 1, the
fraction is in simplest form.
3
1
3
÷
=
4
1
4
Greatest Common Factor

The greatest common
factor is the largest factor
between two numbers.
12 = 1, 2, 3, 4, 6, 12
18 = 1, 2, 3, 6, 9, 18
What is the Greatest
Common Factor?
8 = 1, 2, 4, 8
12 = 1, 2, 3, 4, 6, 12
What is the Greatest
Common Factor?
8 = 1, 2, 4, 8
14 = 1, 2, 7,14
What is the Greatest
Common Factor?
6 = 1, 2, 3, 6
18 = 1, 2, 3, 6, 9, 15
What is the Greatest
Common Factor?
6 = 1, 2, 3, 6
12 = 1, 2, 3, 4, 6, 12
What is the Greatest
Common Factor?
8 = 1, 2, 4, 8
16 = 1, 2, 4, 8, 16
What is the Greatest
Common Factor?
8 = 1, 2, 4, 8
10 = 1, 2, 5, 10
What is the Greatest
Common Factor?
3 = 1, 3
6 = 1, 2, 3, 6
What is the Greatest
Common Factor?
4 = 1, 2, 4
6 = 1, 2, 3, 6
What is the Greatest
Common Factor?
7 = 1, 7,
21 = 1, 3, 7, 21
What is the Greatest
Common Factor?
15 = 1, 3, 5, 15
24 = 1, 2, 3, 8, 12, 24
Shortcuts to reducing fractions
If the fraction has any zeros, you can
cross out any of the zeros. But you can
only cross out any zeros if both the
numerator and denominator have zeros.
For example:
10 = 1
10
100
How to Find the Simplest Form
of a Fraction

Find the greatest common
factor of the numerator and the
denominator and divide both
the numerator and the
denominator by that number.
12
6
2
÷
=
18
6
3
Simplify or Reduce This
Fraction
12
6
2
÷ =
18
6
3
Simplify or Reduce This
Fraction
9
3
3
÷ =
21 3
7
Simplify or Reduce This
Fraction
12
4
3
÷ =
20 4
5
Simplify or Reduce This
Fraction
10
5
2
÷ =
15
5
3
Simplify or Reduce This
Fraction
10
2
5
÷ =
16
2
8
Simplify or Reduce This
Fraction
12
4
3
÷ =
16
4
4
Simplify or Reduce This
Fraction
3
3
1
÷ =
12
3
4
Simplify or Reduce This
Fraction
2
2
1
÷ =
8
2
4
Simplify or Reduce This
Fraction
2
2
1
÷ =
4
2
2
Simplify or Reduce This
Fraction
6
3
2
÷ =
9
3
3
Simplify or Reduce This
Fraction
6
2
3
÷ =
8
2
4
It’s important to know how to reduce
fractions to their simplest form because…
It will be on the CST’s!
It is easier to work with larger parts
of fractions that it is to work with
smaller parts.
Why else is it important?
What did you learn?
•What are factors?
•What are factors of 20 and 30? What is the
greatest common factor?
•Reduce the fraction 20/100 to lowest terms?
•Are there any shortcuts to reducing fractions?