Good knowledge of multiplying fractions! 

Before you start this lesson about multiplying fractions, I recommend that you become familiar with the multiplication table.

Multiplying fractions is very easy. However, I would like to introduce the topic with an interesting example about pizza.

Suppose that you bought a medium pizza and the pizza has 8 slices.

If someone eats half of your pizza, or 4 slices, you are left with
4 / 8
From the illustration below, you can also see that the leftover is the same as  
1 / 2
Half a pizza or 1/2

If you decide that you are only going to eat 1 slice out of the 4 slices remaining, you are eating  
1 / 4
  of the leftover.

Remember that the leftover is  
1 / 2
You can also argue that you only ate 1 slice out of 8 slices or  
1 / 8

One-eighth


Thus, we can see that eating 1/4 of 1/2 is the same as eating 1/8.

Another way to get  
1 / 8
 is to perform the following multiplication:

1 / 4
×
1 / 2
=
1 / 8

We get this answer by multiplying the numbers on top (numerators): 1 × 1 = 1

and by multiplying the numbers at the bottom (denominators): 4 × 2 = 8

This is an interesting result, but all you need to remember is the following:

When you multiply fractions, multiply the numerators together

Then multiply the denominators together.

Notice also that the word 'of' means multiplication.

More examples

3 / 5
×
4 / 7
=
12 / 35

Sometimes, it is a good idea to simplify the fractions before multiplying.

Take a look at the following example:

10 / 20
×
3 / 15


10 / 20
 
can be simplified as  
1 / 2


Divide the numerator and the denominator by 10


3 / 15
 
can be simplified as  
1 / 5


Divide the numerator and the denominator by 3

This way, it is easier to do the multiplication to get  
1 / 10

Sometimes, it is a good idea to simplify the fractions before multiplying.

Take a look at the following example:

10 / 20
×
3 / 15

10 / 20
 
can be simplified as  
1 / 2


After we divide the numerator and the denominator by 10



3 / 15
 
can be simplified as  
1 / 5


After we divide the numerator and the denominator by 3



This way, it is easier to do the multiplication to get  
1 / 10

Multiplying fractions quiz. Check to see if you can now multiply fractions.

Recent Articles

  1. Mean of a Discrete Random Variable

    Jul 20, 21 10:08 AM

    Learn to calculate the mean of a discrete random variable with this easy to follow lesson

    Read More

Enjoy this page? Please pay it forward. Here's how...

Would you prefer to share this page with others by linking to it?

  1. Click on the HTML link code below.
  2. Copy and paste it, adding a note of your own, into your blog, a Web page, forums, a blog comment, your Facebook account, or anywhere that someone would find this page valuable.