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### Course: 6th grade (Illustrative Mathematics) > Unit 4

Lesson 3: Lesson 11: Using an algorithm to divide fractions# Writing fraction division story problems

Darryl spent 24 1/4 hours writing a novel chapter, and we explore situations where dividing 24 1/4 by 3/4 is meaningful. Two examples include calculating the number of days spent writing with 45-minute daily sessions and determining the time spent illustrating if it's 3/4 as long as writing. Creative thinking helps uncover more scenarios. Created by Sal Khan.

## Want to join the conversation?

- Someone pls help...I am very confused.

I was trying to do the exercise but had to come back to the video but I couldn't understand what was going on.

Pls help.(22 votes) - this make no sense(17 votes)
- it dose make no sense(6 votes)

- i need help how do i understand this??(14 votes)
- idk try looking i(3 votes)

- the questions are always different and this guy always picks the hard way(13 votes)
- this makes no sense(10 votes)
- dude this video does not help in anyway btw The quiz in the next lesson is like 2x harder(9 votes)
- 💀Fr can someone help me understand this..(9 votes)
- I don't get it. I mean, the video barely makes sense to me, and the quiz is so much harder, why?(8 votes)
- i saw tons of comments saying they didn't understand this so ill help out:)

lets say we have 2 1/4 divided by 1/3

you first would take the 2 and 1/4 and convert it into 9/4

now you take the 9/4 and you can multiply by the reciprocal (keep change flip)

now its just 9/4 x 1/3

to get the answer just multiply straight across

9 x 1 is nine so that's the first part

than you multiply 4x3 and than you get 12

the answer would be 12/9

than you will simplify (unless its already simplified fully or as low as possible)(7 votes)- I'm not trying to understand how to divide because I understand that, i don't understand werther things make sense in a certain context or not. i had a situation here in khan academy where kids from school got a number of things to recycle and someone decided to divided that number by another number to find the volume of each bag which appereantly is correct, but to me it was not because to find the volume you need to multiplye depth, height and lenght.(2 votes)

## Video transcript

- [Instructor] We're told
that Darryl spent 24 1/4 hours writing a chapter of a novel. And then they ask us, what
are some things that 24 1/4 divided by 3/4 could
represent in this context? So my understanding of this is they really just want us
to be a little bit creative about what division by a fraction could represent in a given context. So, well, one, I encourage
you to pause your video and think about that a little
bit before I think about it. But one thing I think about
is, well, if I took 24 1/4, and if I were to divide it
into chunks of 3/4 of an hour because this is in hours,
how many chunks would I have? So this could represent,
let's say that he spent, he spent 45 minutes, which is the same thing of 3/4 of an hour, 3/4 hours, of an hour, I should say, 3/4 of an hour each day. How many days, how many days
did it take him, did it take? And then you could evaluate
this, 24 1/4 divided by 3/4. We've talked about how to
evaluate that in other videos. So that's one context. Another one could be some
type of a comparison. So let's say that 24 1/4 is 3/4 of the amount of time that he spent doing something else. So let's say, so this is now a
completely different context. I'm gonna put a line here. I'll do it in a different
color just to make it clear it's a different context. So another one could be to
justify doing this division, he spent 3/4 as long writing, writing as he spent illustrating, illustrating the chapter. And so then the question is how long did he spend illustrating? How long did he spend illustrating? Now, I really want you
to think about this one. My brain, actually, this one
takes a little bit longer for my brain to process. But when you think about it, if you divide by a fraction
that is less than one, you're gonna get a number larger than the one that you're dealing with. Or another way to think about it, the time spent illustrating,
time illustrating, I'll write it like this, the time illustrating times 3/4 should be equal to the time spent writing because it says he spent, or he spent, I forgot to write that, he spent 3/4 as long writing
as he spent illustrating. So time illustrating times 3/4 should be time writing or 24 1/4. So if something times
3/4 is equal to 24 1/4, then 24 1/4 divided by 3/4 should be equal to time illustrating. So these are the two
contexts that I can think of that might make sense, but you might be able to think of others.