A fraction is in lowest form when the greatest common factor (GCF) of the numerator and denominator is 1. To express a fraction in lowest form, you find the GCF of the numerator and denominator and divide both by the GCF. This reduces the fraction to a form where the numerator and denominator cannot be further divided.

1. Fractions in
Lowest Form

2. When can we say
that the fraction is
in lowest form?

3. A fraction is in lowest
form when the greatest
common factor (GCF) of the
numerator and the
denominator is 1.
Lowest Form of Fractions

4. Fractions in
Lowest Form
Fractions NOT in
Lowest Form
1
2
2
3
3
4
3
7
5
8
2
4
4
6
8
10
8
12
16
24

5. is the biggest factor
common to two or more
numbers.
Greatest Common Factor

6. How do you
express a fraction
in lowest form?

7. To express a fraction in
lowest form, follow these
steps:

8. - Find the GCF of the
numerator and the
denominator.
Step 1:

9. - Divide the
numerator and the
denominator by their
GCF.
Step 2:

10. Look at the fraction given below.
STEP 1: Find the GCF of the numerator
and denominator
6
8
The common factors are 1 and 2.
The GCF is 2.
6 = 1, 2, 3, 6
8 = 1, 2, 4, 8

11. Look at the fraction given below.
STEP 2: Divide the numerator and
denominator both by 2.
6
8
2
2
6
8
=

So,
Now we can not divide 3 and 4 both by
any number.
So, we can say that 3
4
is the lowest form of 6
8
3
4
6 divided by 2 is 3.
8 divided by 2 is 4.

12. Reduce the given fraction to its lowest form.
We can divide both, the numerator
and the denominator by 3.
The lowest form of 3
9
1
3
is
We can divide both, the numerator
and the denominator by 2.
The lowest form of 10
12
5
6
is
10
12
3
9
3
3
3
9
=
 1
3
2
2
10
12
=
 5
6

13. 2
8
1
4
Choose the fractions which
are in the lowest form.
3
9
5
6
5
7
4
12
3
5
9
18
3
8
6
14
4
9
8
12
Back
3
3
2
2
9
9
2
2
2
2
4
4