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### Course: Staging content lifeboat > Unit 14

Lesson 34: 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
- Multiplying fractions and whole numbers 2
- Multiply fractions and whole numbers
- Multiply fractions and whole numbers visually

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# Multiplying fractions and whole numbers 2

Sal multiplies 6 x 1/4 and supports the answer by drawing a fraction model. Created by Sal Khan and Monterey Institute for Technology and Education.

## Want to join the conversation?

- It's easier to think of fractions as people with things. If you have 6 candy bars and you split them with JUST yourself, how many candy bars do you get to keep? 6 bars/1 person = 6 bars per person, which is just you. And if you had 6 candy bars for you and 5 friends, it is 6/6, which is 1 bar for you or 1 bar per person.(5 votes)

- This is not math related, but technical: How do I answer with a mixed number in the assignments? For example, it asks to represent 3.11 as a mixed number, but when I write 3+1/10+1/100, it tells me that I have too many characters. How do I fix this?(5 votes)
- to write a mixed number such as three and a half you write 3 space 1/2 and it looks like this 3 1/2

To write 3.11 as a mixed number first change the .11 to a fraction = it is 11/100, so 3.11 is written 3 11/100 with a space between the 3 and 11/100

You can also write the answer as an improper fraction - 3 1/2 becomes 7/2

3 11/100 becomes 311/100

Hope this helps.(6 votes)

- What os a mixed number or a whole(4 votes)
- a mixed number is 25 1/8 and a whole number is 25(3 votes)

- I really need help with multiplying fractions with whole numbers, and KHAN does not have any videos to help me with them! Please, can someone help me? It is a pain, because my math program is not teaching me it, but it is asking questions relating to them.Someone,please help fast -Thanks!,Corynn.(3 votes)
- Well, you just need to turn the whole number into a fraction. Okay, let's say I am multiplying 2 x 1/2; I would turn the 2 into a fraction by putting a 1 under the 2, like this, 2/1. That means it's 2 divided by 1 (which is 2). So now I have 2/1 x 1/2, now I would ask myself, what is 2 x 1? 2! The same equation is on the bottom, 1 x 2. 2! Now my answer is 2/2. So now if you want to convert that into a whole number, you do 2 divided by 2. Which is 1. So 1 is my answer!(3 votes)

- How is it a mixed number why is it called that(3 votes)
- Because it is written as a mix between a whole number and a fraction.(3 votes)

- how do you multiply

a mixed number by a whole number(3 votes)- First start off by changing the mixed number to a improper fraction, so for example, 1 3/4 to 7/4. Now to give you an idea on how to do this let me give you an example. How to multiply 2 4/5 to 5? Well start off by changing 2 4/5 to an improper fraction, which is 14/5. So now 14/5 times 5 (or if you want to visualize this better you may write it as 5/1). So the numerator times the numerator will be 14 times 5, which makes it 70. Denominator times the other denominator makes it still 5, the answer will be 70/5. This can be simplified further to 14. Hope this helped!(3 votes)

- Why specifically do you have to divide while multiplying fractions and mixed numbers?(3 votes)
- please be more specific. multiplying by fractions is dividing by whole numbers. eg 2*1/2 is 4 (2 goes into a half four times) I'm not sure if that's what you mean?(3 votes)

- What If the numbers are not even numbers?(2 votes)
- It doesn't matter . You just do the same thing. Just multiply and simply if needed. Try to find a video that focus on whole number than 2 or even numbers.(2 votes)

- how do you multiply fractions?(2 votes)
- Thank you very much because i have a test on this tommorow and i didn't understand the lesson in class(2 votes)

## Video transcript

Multiply 6 times 1/4. Simplify your answer and write
it as a mixed number. So let's just do the
multiplication. So at first when you try to
multiply 6 times 1/4, you'll be like, well, gee, I know
how to multiply a fraction times a fraction. I know how to multiply a whole
number times a whole number, but what about a whole number
times a fraction? And kind of the key insight
you need here is that any whole number can be written
as a fraction. We can rewrite 6
as 6/1, right? 6 divided by 1 is 6. 6 ones is 6. Depending how you think about
it, this is exactly the same thing as 6. So we just rewrote our whole
number as a fraction. You can do it for any number. 10 is the same thing as 10/1. So this become 6/1 times
1/4, and then we just multiply the fraction. We multiply the numerators, so
this is equal to 6 times 1 as our numerator. Let me do that in
another color. So this becomes 6 times 1 for
our numerator and 1 times 4 for our denominator, for the
number on the bottom. And so this will become
6 over 4. And right now, it's just as an
improper fraction and it's also not in lowest terms. You
immediately see 6 and 4 are both divisible by 2, so let's
divide them both by 2. If you divide 6 by 2--
and I'll do it in a new color again. If you divide 6 by
2, you get 3. If you divide 4 by 2, you get
2, so this is equal to 3/2. So it's still written as
an improper fraction. We now have to write it
as a mixed a number. And the process for writing it
as a mixed number, you just divide the denominator into the
numerator, so this just becomes 2 into 3. Divide 2 into 3. 2 goes into 3 one time. 1 times 2 is 2. You subtract. You have a remainder of 1. So this will become one whole
and 1/2 left over. So this is 1 and 1/2. So that's our right answer. We've just simplified the answer
and wrote it is a mixed number or we could simplify
it at this stage. We could say right here, well,
look, we could divide what's eventually going to be in the
numerator by 2 and get a 3 there, and divide what's
eventually in the denominator by 2 and get a 2 there. 3 times 1 is 3. 1 times 2 is 2, so it's 3/2. And you do this exact
same process. You say that 3/2 is the same
thing as 1 and 1/2. Either one of those will work. Now let's think about why
this makes sense. Let's think about what
6 times 1/4 is. Let me draw 1/4. Let's say that that is
1/4 right there, and let's do six of them. So that's 1/4, that's 2/4 that's
3/4, that's 4/4, which would be a whole, and then
you have 5/4, and then you have 6/4. So this is 6 times 1/4. This right here is 4/4. This right here is 4 over 4,
which is equal to a 1, so this is equal to 1. And then this right here
is two 1/4's, or this right here is 2/4. You can imagine this is two out
of a potential, if a whole has to have two more of them,
has to have four of them. so this is 1 and-- let me do it
in the same colors-- 1 and 1/2, right? 2 out of 4 is the same thing as
1/2, so this right here is one out of a possible
one, and then two. So this is 1 and 1/2, which is
exactly what we got before.