I've got a question. In the first example, Sal compares the width of the 1st rectangle which is 3m with the length of the 2nd rectangle which is 9m. And he said "rectangle NO.1 has a width of 3m and rectangle No.2 has a width of 9m". I want to ask if we distinguish length from width in Maths or in talking about shapes

Typically, we reference the dimension that is most parallel with the directions left and right when looking at four sided objects as width, and the up/down sides are referred to as height. But technically, you could refer to them the other way around if you wanted to. You must be consistent, however, if you are comparing multiple objects.

Here is something interesting: I have a holiday from the 10th until the 20th of January. How many days off have I got? 20-10 = 10 But if you count the number of days with your hands, you discover that you have 11 days off! Can anyone explain this sorcery?

This is because you really start counting from zero. When you normally count it goes like 1 2 3 4 5 6 7 8 9 10, which is 10 numbers If you count from zero it is: 0 1 2 3 4 5 6 7 8 9 10, which is 11 numbers In this case you count from 10th like this: 10 11 12 13 14 15 16 17 18 19 20 and it resembles counting from zero (if you ignore number in ten's position). When you have holiday from 1st to 10th, it is 10 days. When you have holiday from 10th to 20th, it is 11 days because you have to add the 10th day. In fact, you have to add 1 every time when you count the number of days or anything where you count in the starting number of range. For example: 10 - 1 = 9, but 1 to 10 is 10 numbers 25 - 4 = 21, but 4 to 25 is 22 numbers

Isn't this essentially comparing terms? In the first exercise, you can see that Sal straight out gives us the lengths, and this turns into a comparison problem. The only difference I see is that this is a bit for visual. But there are some comparison problems on Khan Academy that include visual representations, so isn't this exercise irreverent if you know to compare 2 terms?

This time we are comparing two things using a ruler for each one. That is opposed to comparing one object's length with a ruler and another object.

how many inches does a yard stick have ?

A yardstick consists of 3 feet, and each foot has 12 inches, so 3 * 12 = 36 inches, 36 inches are in a yardstick

Can you multiply fractions

yes, for example 1/2 x 2 = 1 or you could multiply 1/4 times 4 to get 1 also

I will never understand this. Can someone explain?

You compare the two lengths of the objects by first ensuring that both objects are measured in the same measuring unit, such as centimeters. You then can compare the lengths. The object with the bigger number is longer than the object with the smaller number. Here's an example: Rectangle A is 5 centimeters long. Rectangle B is 8 centimeters long. Compare the length of the two rectangles. Rectangle A _ Rectangle B 5 centimeters _ 8 centimeters 8 is a larger number than 5, so.. 5 centimeters < 8 centimeters. Therefore, Rectangle A < Rectangle B Because 8 is greater than 5, rectangle B is longer than rectangle A.

Main content

Early math review

Course: Early math review > Unit 7

Lesson 3: Comparing and estimating length

Comparing lengths

Name: Comparing lengths
Uploaded: 2015-03-17T18:59:58Z
Description: Sal uses a ruler to compare the lengths of different objects.

Google Classroom

Sal uses a ruler to compare the lengths of different objects.

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Aulia Aliyev
Posted 5 years ago. Direct link to Aulia Aliyev's post “Here is something interes...”
Here is something interesting:

I have a holiday from the 10th until the 20th of January. How many days off have I got?
20-10 = 10
But if you count the number of days with your hands, you discover that you have 11 days off!
Can anyone explain this sorcery?
Button navigates to signup pageComment on Aulia Aliyev's post “Here is something interes...”
(7 votes)
Answer
- Tonda Minařík
  Posted 5 years ago. Direct link to Tonda Minařík's post “This is because you reall...”
  This is because you really start counting from zero.
  
  When you normally count it goes like 1 2 3 4 5 6 7 8 9 10, which is 10 numbers
  If you count from zero it is: 0 1 2 3 4 5 6 7 8 9 10, which is 11 numbers
  In this case you count from 10th like this: 10 11 12 13 14 15 16 17 18 19 20 and it resembles counting from zero (if you ignore number in ten's position).
  
  When you have holiday from 1st to 10th, it is 10 days.
  When you have holiday from 10th to 20th, it is 11 days because you have to add the 10th day.
  
  In fact, you have to add 1 every time when you count the number of days or anything where you count in the starting number of range.
  For example:
  10 - 1 = 9, but 1 to 10 is 10 numbers
  25 - 4 = 21, but 4 to 25 is 22 numbers
  Comment on Tonda Minařík's post “This is because you reall...”
  (18 votes)
Alina gonzalez
Posted 5 years ago. Direct link to Alina gonzalez's post “how many inches does a ya...”
how many inches does a yard stick have ?
Button navigates to signup pageComment on Alina gonzalez's post “how many inches does a ya...”
(4 votes)
Answer
- Anthony Fritz
  Posted 5 years ago. Direct link to Anthony Fritz's post “A yardstick consists of 3...”
  A yardstick consists of 3 feet, and each foot has 12 inches, so 3 * 12 = 36 inches,
  
  36 inches are in a yardstick
  Comment on Anthony Fritz's post “A yardstick consists of 3...”
  (13 votes)
Tyler P
Posted 8 years ago. Direct link to Tyler P's post “Isn't this essentially co...”
Isn't this essentially comparing terms? In the first exercise, you can see that Sal straight out gives us the lengths, and this turns into a comparison problem. The only difference I see is that this is a bit for visual. But there are some comparison problems on Khan Academy that include visual representations, so isn't this exercise irreverent if you know to compare 2 terms?
Button navigates to signup pageButton navigates to signup page
(7 votes)
Answer
- John Finigan
  Posted 7 years ago. Direct link to John Finigan's post “This time we are comparin...”
  This time we are comparing two things using a ruler for each one. That is opposed to comparing one object's length with a ruler and another object.
  Button navigates to signup page
  (7 votes)
Sam Du
Posted 7 years ago. Direct link to Sam Du's post “I've got a question. In t...”
I've got a question. In the first example, Sal compares the width of the 1st rectangle which is 3m with the length of the 2nd rectangle which is 9m. And he said "rectangle NO.1 has a width of 3m and rectangle No.2 has a width of 9m". I want to ask if we distinguish length from width in Maths or in talking about shapes
Button navigates to signup pageButton navigates to signup page
(8 votes)
Answer
- Chris Petersen
  Posted 7 years ago. Direct link to Chris Petersen's post “Typically, we reference t...”
  Typically, we reference the dimension that is most parallel with the directions left and right when looking at four sided objects as width, and the up/down sides are referred to as height. But technically, you could refer to them the other way around if you wanted to. You must be consistent, however, if you are comparing multiple objects.
  Comment on Chris Petersen's post “Typically, we reference t...”
  (4 votes)
ripon7
Posted 7 years ago. Direct link to ripon7's post “how to do millimetre to c...”
how to do millimetre to centimetre
Button navigates to signup pageButton navigates to signup page
(2 votes)
Answer
Sujal Chaudhary
Posted 4 years ago. Direct link to Sujal Chaudhary's post “what ismean by length of ...”
what ismean by length of object is 4 meter
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(6 votes)
Answer
Abimbola Bello
Posted 7 years ago. Direct link to Abimbola Bello's post “I will never understand t...”
I will never understand this. Can someone explain?
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(2 votes)
Answer
- Brooke Dragonflame
  Posted 7 years ago. Direct link to Brooke Dragonflame's post “You compare the two lengt...”
  You compare the two lengths of the objects by first ensuring that both objects are measured in the same measuring unit, such as centimeters. You then can compare the lengths. The object with the bigger number is longer than the object with the smaller number.
  
  Here's an example:
  
  Rectangle A is 5 centimeters long.
  Rectangle B is 8 centimeters long.
  Compare the length of the two rectangles.
  
  Rectangle A _ Rectangle B
  5 centimeters _ 8 centimeters
  
  8 is a larger number than 5, so..
  5 centimeters < 8 centimeters.
  
  Therefore,
  Rectangle A < Rectangle B
  
  Because 8 is greater than 5, rectangle B is longer than rectangle A.
  Comment on Brooke Dragonflame's post “You compare the two lengt...”
  (5 votes)
Peyton vandehey miller
Posted 3 years ago. Direct link to Peyton vandehey miller's post “Can you multiply fraction...”
Can you multiply fractions
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(4 votes)
Answer
- Potato
  Posted 3 years ago. Direct link to Potato's post “yes, for example 1/2 x 2 ...”
  yes, for example 1/2 x 2 = 1 or you could multiply 1/4 times 4 to get 1 also
  Button navigates to signup page
  (3 votes)
Ambar.Campos
Posted 8 years ago. Direct link to Ambar.Campos's post “what would happen if you ...”
what would happen if you cant use a ruler to measure? I have watch another video and you had to measure with a rectangle or little squares is that the only way or there can be more?
Button navigates to signup pageComment on Ambar.Campos's post “what would happen if you ...”
(3 votes)
Answer
dadYo19789898
Posted 7 years ago. Direct link to dadYo19789898's post “how do you do this it is ...”
how do you do this it is so confusing
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(1 vote)
Answer

Video transcript

- Rectangle 1 is blank meters blank than Rectangle 2. Let's look at this. Rectangle 1 has a width of 3 meters. Rectangle 2 has a width of 9 meters. Rectangle 1 is, if you compare 3 to 9, it's going to be 6 meters shorter. 6 meters shorter than Rectangle 2. You see that right over here, because 3 meters is 6 less than 9 meters. It's 6 meters, and you know it's not going to be longer. Rectangle 1 is definitely ... it has less width. It's definitely shorter than Rectangle 2. It's 6 meters shorter than Rectangle 2. Let's do a few more of these. Line 1 is blank centimeters long. We can measure it. We could measure it right over here. Line 1 is 9 centimeters long. 9 centimeters long. Line 2 is blank centimeters long. Let me actually zoom this in a little bit so that we can see it a little bit better. Line 2 is blank centimeters long. Line 2 is 5 centimeters long. Let me zoom in a little bit more even. Line 2 is 5 centimeters long. Line 1 is blank centimeters blank than Line 2. Well, Line 1 is 9 verses 5, so it's 4 centimeters longer than Line 2. Line 1 is 4 centimeters longer than Line 2. You can see it right over here. To go from Line 2 to Line 1, you'd have to add 1, 2, 3, 4 centimeters. Let's do a few more of these. Triangle 1 is blank centimeters long. We can just use a ruler to measure that it's 3 centimeters long. Triangle 2 is blank centimeters long. Let me scroll down to look at Triangle 2. Triangle 2 is 5 centimeters long. Triangle 2 is 5 centimeters long. Triangle 1 is blank centimeters blank than Triangle 2. Well, Triangle 1 is 2 centimeters shorter than Triangle 2. 3 is 2 less than 5. It's going to be 2 centimeters shorter. Remember, Triangle 1, we see it's shorter it's smaller than Triangle 2, so it makes since that it's shorter. How much shorter? 2 centimeters because 3 centimeters compared to 5 centimeters. Let's do one more of these. Rectangle 1 is blank centimeters long. We can just look right over here. It's 9 centimeters long. We have one end of the ruler at one end of the rectangle, and then we just measure off 9 centimeters. Rectangle 2 is, well, it looks like it's 6 centimeters long. 6 centimeters long. Rectangle 1 is longer, and it's 3 centimeters longer than Rectangle 2. 9 centimeters is 3 centimeters more than 6 centimeters. It's 3 centimeters longer. Rectangle 1 is the longer Rectangle. Then, we're done.