Main content

## Staging content lifeboat

### Unit 14: Lesson 35

Multiplying fractions and whole numbers word problems# Multiplying fractions word problem: milk

Sal solves a multiplication fraction word problem about milk. Created by Sal Khan.

## Want to join the conversation?

- how is 6/1 = to 6(0 votes)
- because 1/1 is equal to 1 whole so 6/1 is equal to 6(8 votes)

- what does energy points mean(0 votes)
- Energy Points are points you earn for working on assignments and/or goals in Khan Academy. Hope this helps! :)(8 votes)

- I got confused about something about halfway through. How exactly does 20/5 equal 4??(1 vote)
- 20 ÷ 5 = 4. If the fraction is improper check if you can divided the numerator by the denominator.

Happy to help!(4 votes)

- do you now Wikipidea.(3 votes)
- but l have milk of water(1 vote)
- I still don't get it

What do you meen(1 vote) - what does energy points mean(0 votes)
- An energy point is something you earn when you complete a lesson, test, or watch a video. The more energy points you have, the better avatars you get. For example, my avatar is a level four Duskpin. You need to have a total of 100,000 energy points. You don't need to buy the avatars because Khan Academy just unlocks the available avatars immediately. You can also earn badges by accumulating a specific amount of energy points. That is basically my summary of energy points, and if I put anything that is incorrect, please tell me!(3 votes)

- show me how to solve. Lana was trying to collect 3 pounds of cans . If she collects one-fourth of a pound each day, how many days will it take to collect 3 pounds,(0 votes)
- what is a gallon ?(0 votes)
- its the largest unit to measure liquid hope it helped! :D(1 vote)

- I got confused about something about halfway through. How exactly does 20/5 equal 4??(0 votes)

## Video transcript

If there are 6 people
in your family, and each person drinks 4/5 of
a gallon of milk each month, between what two whole numbers
is the number of gallons of milk your family
will drink each month? So let's think about
this a little bit. So I've got my milk gallon
here for inspiration. So there's 6 people
in my family, or in your family, whoever's
family we're talking about. And each of them drink
4/5 of a gallon per month. So we're going to go 6
times 4/5, or 4/5 times 6. Now, what is this
going to be equal to? Well, there are several ways
we could think about this. One, we can express
6 as a fraction. We could say that this is the
same thing as 6/1 times 4/5. And you multiply the numerators. You multiply the denominators. 6 times 4 is 24. And 1 times 5 is 5. So 24/5 gallons are going
to be drunk every month. And this is the same
thing-- let's see, 5 goes into 20 evenly
and has a remainder of 4. So we could write this
as 20/5 plus 4/5 5-- let me move over a little
bit so I don't run out of space, which
is the same thing. This is 4. So this is 4 and 4/5. So that's one way
to think about it. The other way, you could
think of this as 4/5 times 6, which is the same thing
as 4/5 plus 4/5 plus 4/5-- I think you get the idea--
plus 4/5 plus 4/5 plus 4/5. We took literally six 4/5's
and added them together. And what's this
going to be equal to? Well, this is going to
be 4 plus 4 plus 4 plus 4 plus 4 plus 4 over 5. This is how many 1/5's we have. Well, this is 6
times 4, or you could say 4 times 6, over 5,
which is equal to 24 over 5, which we've already
figured out is 4 and 4/5. So either way,
we're going to drink 4 and 4/5 gallons per month. Now let's try to answer
the actual question. Between what two whole numbers? Well, between 4 and
5 gallons a month. 4 and 4/5 is right
in between 4 and 5. We got it right.