Find the Greatest Common Factor

1
Find the Greatest Common Factor
20
24
1 x 20
1 x 24
2 x 10
2 x 12
4 x 5
3 x 8
4 x 6
20 24
5 6
Dividing by the GCF puts a fraction in simplest
form!
4
4
2
Find the Greatest Common Factor
9
10
1 x 9
1 x 10
3 x 3
2 x 5
9_ 10
is in simplest form
If the GCF is 1, the fraction is in simplest form!
3
Simplest Form
GCF

• Divide by the ________ to write fractions in
  simplest form.

12 15
4 5
8 9
16 18
3
2
3
2
12
15
16
18
1 x 12
1 x 15
1 x 16
1 x 18
2 x 8
2 x 9
2 x 6
3 x 5
3 x 4
4 x 4
3 x 6

• When we write fractions in simplest form, we are
  writing equivalent fractions!

4
Equivalent Fractions
Fractions that represent the same value
4 8
1 2

5
Simplest Form

• If you dont find the GCF, keep dividing until
  there are no factors in common.

16 24
8 12
4 6
2 3
2
2
2
2
2
2

• Use divisibility tests to find common factors!

6
Equivalent Fractions
Fractions that represent the same value
4 8
1 2

7
Divisible By
A number can be divided by the other number with
a remainder of zero
Ex. 28 is divisible by 4 (28 4 7
with no remainder)
8
Which factors are the numbers divisible by?2,
3, 5, 9, 10

• 55

96
5
2, 3
180
17
2, 3, 5, 9, 10
prime