If you're seeing this message, it means we're having trouble loading external resources on our website.

If you're behind a web filter, please make sure that the domains *.kastatic.org and *.kasandbox.org are unblocked.

### Course: Staging content lifeboat>Unit 14

Lesson 34: Multiplying fractions and whole numbers

# Multiplying fractions and whole numbers

Multiplying fractions is about combining parts of a whole. When you multiply two fractions together, you're taking a part of a part. When you multiply a fraction by a whole number, you're taking multiple copies of that fraction. In both cases, the result is a new fraction that represents a different part of a whole. Created by Sal Khan.

## Want to join the conversation?

• If you have to add a fraction by a whole number can we just add the number and not turn it into a fraction?
• Yes. This will create what math likes to call a 'mixed number', at least, when you're adding.
Take this example:
You order two large pepperoni pizzas for a big party you're throwing with your friends. They eat a few slices, and you're left with only two thirds for one pizza. However, the other pizza is still whole.
We can solve this problem by creating a mixed number, which is made by simply adding a whole number and a fraction together, like so: one and two thirds. You can also express it as 1 2/3 or 1+2/3.
Hope this helped.
• i stil dont get how 2/3 times 6 is equal to 4
• Whenever you have a series of mulitplications and divisons they are meant to be done left to right. In this case, 2/3 = 0.666.... repeating. 0.6666... x 6 = 3.9999....6. The reason for this number is that the 0.666 is meant to be endless. The more 6s you would add, the closer the result would be to 4.
Another way to do this, which is more precise, would be to treat the numbers as fractions, 2/3 x 6/1. In this case, 2x6 = 12, then 12/3 = 4. We cannot do 2/(3x6) because that would be the same as multiplying by 1/6, not 6/1.
• Is there another way to do this?
• The easiest way to think about multiplying fractions by whole numbers is to multiply the numerator of the fraction by your integer and then bring over the deonominator.

3/4 * 8 can be thought of as (3*8)/4, or 24/4, or 6.
1/2 * 7 is (1*7)/2, or 7/2
6/23 * 3 is(6*3)/23, or 12/23
• At , why did he multiply the whole number with a numerator even though we learned to multiply with the denominator can someone describe me please?
• This is because sal has 6 2/3, but he wants to add them together, not find a equivalent fraction. You would use the denominator when trying to find an equivalent fraction.
• The way he showed it is for people that do not know to use multiplication. I can see how people can get confused on this.
• how do you figure out if a question is right or wrong