Why do we need parentheses?

We use the parentheses to make it clear that we are *dividing the entire result* of `58-13` (number of pages remaining) by `5` to figure out the number of days to finish the book. Without it, the equation would look like `d = 58-13/5`, which would only divide the `13`. Hope this helped!

what are parenthesis for

*Parentheses* are () enclosing some part of an expression. They are *grouping symbols*, which _associate_ numbers and operations together. Also, the *Order of Operations* tells us to evaluate groupings first! The video shows how you can find *number of days* to finish a book. Well, you know there's `58` pages in the book, and you have already read `13` pages. So the number of *remaining pages* is `58 - 13`. However, you can read `5` *pages per day* (this is a rate). By dividing number of remaining pages by the rate, you get the *days left*. `(58 - 13)/5` You have to put parentheses to *associate* all of `(58 - 13)` with the number of remaining pages! Otherwise, it would look like `58 - 13/5`, which would only divide the `13` (incorrect). Hope this helped!

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Course: 3rd grade > Unit 8

Lesson 3: One and two-step word problems

Setting up 2-step word problems

Name: Setting up 2-step word problems
Uploaded: 2019-06-17T15:03:37Z
Description: Sal represents 2-step word problems with equations.

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Sal represents 2-step word problems with equations.

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ckevinadv
Posted 3 months ago. Direct link to ckevinadv's post “Why do we need parenthese...”
Why do we need parentheses?
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(4 votes)
Answer
- TheReal3A
  Posted 2 months ago. Direct link to TheReal3A's post “We use the parentheses to...”
  We use the parentheses to make it clear that we are dividing the entire result of 58-13 (number of pages remaining) by 5 to figure out the number of days to finish the book.
  Without it, the equation would look like d = 58-13/5, which would only divide the 13.
  Hope this helped!
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  (10 votes)
Smaran
Posted 22 days ago. Direct link to Smaran's post “what are parenthesis for”
what are parenthesis for
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(1 vote)
Answer
- TheReal3A
  Posted 13 days ago. Direct link to TheReal3A's post “*Parentheses* are () encl...”
  Parentheses are () enclosing some part of an expression. They are grouping symbols, which associate numbers and operations together.
  Also, the Order of Operations tells us to evaluate groupings first!
  
  The video shows how you can find number of days to finish a book.
  Well, you know there's 58 pages in the book, and you have already read 13 pages.
  So the number of remaining pages is 58 - 13.
  However, you can read 5 pages per day (this is a rate). By dividing number of remaining pages by the rate, you get the days left.
  (58 - 13)/5
  You have to put parentheses to associate all of (58 - 13) with the number of remaining pages! Otherwise, it would look like 58 - 13/5, which would only divide the 13 (incorrect).
  
  Hope this helped!
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  (2 votes)
sarahadelaide.smith
Posted 8 days ago. Direct link to sarahadelaide.smith's post “Why parenthesis I mean ca...”
Why parenthesis I mean can't you just do the problem without parenthesis?
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(1 vote)
Answer
- TheReal3A
  Posted 7 days ago. Direct link to TheReal3A's post “Feel free to - if you cal...”
  Feel free to - if you calculated remaining pages -> 58 - 13 = 45, then you can use the 45 to calculate remaining days -> 45/5 = 9.
  However if you were asked to show the entire expression, you can leave it as (58 - 13)/5
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oashish
Posted 11 hours ago. Direct link to oashish's post “why do we have parenthese...”
why do we have parentheses
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Answer
- Ellie
  Posted 7 hours ago. Direct link to Ellie's post “Hi oashish! We se parenth...”
  Hi oashish! We se parenthesis in math for many things. When you have a number in parenthesis next to another number, it means you have to multiply. If you have an expression in parenthesis, it means that you have to do that expression first in the overall equation. All in all, parenthesis are an essential part of math. Hope this helps. Have a great day! 😁
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Video transcript

- [Instructor] My book is 58 pages. I have already read 13 pages. I plan to read five pages each day until I finish the book. Which equation could I use to find out how many days, d, it will take to finish reading the book? So pause this video and see if you can figure that out. Okay, so let's first think about the important information they're giving us. They're giving us the number of pages that are in the book. They're giving us how much we've already read. We've already read 13 pages. And they also tell us how much we plan to read. I plan to read five pages each day until the book is finished. And then we want an equation that could use to find how many days. And d is how we're going to represent the number of days, let me do it in the same color, it'll take to finish reading the book. All right, so if we knew how many pages we have to read and we were divided by the fact that we're reading five pages per days, well, then that would give us the number of days. So how many pages do we have left to read in the book? Well, the book is 58 pages. We've already read 13, so we could subtract out 13 of those. So this expression right over here, this is how many pages we have left in the book. Let me write that down. How many pages left. And if we wanna figure out how many days it's going to take to read these, we would divide this by how many pages we read each day. And we see that we read five pages each day. So if we divide this by five, then this whole expression, let me do it in this color, this whole expression is going to tell us how many days left. How many days left. And so this is going to be equal to d 'cause d is the number of days left to finish reading the book. Now, if we look at these choices, that's exactly what we have right over here in choice C. We can make sure that these others don't make sense. 58 plus 13, no, that would be a situation where we're reading 13 pages more than the number of pages that are in the book. That doesn't make sense. And that's happening for both choice A and choice B. It would also not make sense to multiply by five because it's not going to take you five times more than the number of pages to read the book. You're going to divide by five. You're reading five pages every day. And we are done.