Main content

## 5th grade

### Unit 6: Lesson 2

Multiplying fractions and whole numbers- Multiplying fractions by whole numbers on a number line
- Multiplying unit fractions and whole numbers
- Multiplying fractions and whole numbers visually
- Multiply fractions and whole numbers visually
- Multiplying fractions and whole numbers
- Multiply fractions and whole numbers

© 2023 Khan AcademyTerms of usePrivacy PolicyCookie Notice

# Multiplying fractions by whole numbers on a number line

Sal multipiies fractions by whole numbers using the number line.

## Want to join the conversation?

- Why does he make the question 5x1/3 so complex when all you have to do is do 1x5=5 and add the 3?(17 votes)
*"All you have to do"*shows that the problem is already intuitive for you to solve. For those where the problem is not yet intuitive to solve, it needs to be explained why the solution works.

Someone is eventually going to ask you "*Why do I have to do 1x5 and why is 1x5=5?*" and you have to be able to explain that in a clear manner.(4 votes)

- Is this hard for you guys?(6 votes)
- It is not hard, simply do the way question says firstly multiply 5 with numerator 1 of fraction, which equals to 5. Then put the denominator 3 as it is. Final answer is to mark 5/3 on the number line.(0 votes)

- what if the number is big this is hard! Help Me...(4 votes)
- Why do we have to mutiply fraction?(2 votes)
- because u need it in life even tho u really want need it unless you want to be something(0 votes)

- why do you have to multiply upper one to upper one and the low one to low one(4 votes)
- Hi can you guys do this(2 votes)
- yes i can do it(1 vote)

- Yes, I understand this, but why would we want to multiply fractions? We could convert them into decimals and easily solve them. So why multiplying fractions?(2 votes)
- It may not seem useful now, but later on you will have algebraic expressions with uknown numbers (x, y, ...) in fractions and in some cases it will be very difficult to write such numbers as decimal values.(2 votes)

- I got 2/7 correct this is so hard!(2 votes)
- Oooooorrrrrrr, y don't we put a 1 underneath the 5 and then multiply 5/1 by 1/3 and still get 5/3. Easy. Y R number lines needed?(2 votes)
- I was stumped but now i made it.(2 votes)

## Video transcript

We're asked to move the orange dot to the number that equals five times 1/3. Alright, so one way to think about it, we just have to move 1/3 five times. So let's do it once, so that's going to be 1/3, you do it twice, you get to 2/3, you do it three times, you get to 3/3, four times, you get to 4/3, five times, you get to 5/3. Five times 1/3 is gonna be 5/3. Or you could say five 1/3, which is the same thing as 5/3, hopefully that makes some sense. Let's do some more examples here. So let's say we need to figure out, so let's see, it says move the orange dot to the number that equals two times 4/3. Alright, so one times 4/3
is just gonna get us to 4/3, and then if we have another 4/3, we're gonna add 4/3 to that, so we're gonna move
another 4/3 to the right. So 4/3 plus 4/3 would get us to 8/3. 8/3, I'm having trouble moving this, 8/3. So one times 4/3 is just 4/3, and then two times 4/3 is 8/3. And notice that's the same
thing as two times four, which is eight, over three, 8/3. Let's do one more of these. So, move the orange dot to the number that equals three times 3/2. So this is gonna be 0/2, that's just zero, so you could do that a zero times 3/2. One times 3/2, well that
will just get us to 3/2. Two times 3/2, we'll add another 3/2, so that'll get us to 6/2. And then three times 3/2, we'll add another 3/2, that gets us to 9/2, and we're done.