What if the 2 numbers were switched? How can you even go below zero?

Below zero there would be negative numbers

How far does negative numbers go? Is it like normal numbers? Never ending?

Yes, Negative numbers go on forever just on the other side of the number line.

How would you represent negative numbers?

Negative numbers represent the distance in the opposite direction on the number line. The negative symbol can be seen as a subtraction sign, because 0 - 5= -5.

Why subtraction has this (-) sign?

It is easier to use the (-) sign is stead of saying plus a negative.

How do you write subtraction of negative numbers?? Like this: -2 - -1? It looks kinda weird to me.

If you are talking about subtracting a negative from a negative it would look like that but with parenthesis. -2-(-1). To write one negative number ,for example, if you solve 6-7 that would be equal to -1.

what if you did 4-5? how would that even be possible? would it be 1?

That is a really good question. In reality you can't subtract more than what you have in the first place. For example, you can't start with 4 apples and then give away 5 of them. However, there are cases in which we can "take away" more than what we started with. Let's take the example above and think about it as steps. If you took 4 steps forward and then 5 steps backward, where would you be? You be 1 step behind where you started, which would be -1.

who made subtraction? as like: who create the subtraction

No particular person created subtraction. Subtraction originated from the concept of removing an amount of something from a collection. Early man was able to grasp the concept of having a number of apples and then taking a certain number away and having less. Soon we understood that you can assign values or names to things ie: this is "one" apple. Everything after that just comes down to what was used to represent a certain number of something, is it "five?" "a grunt" or "cinco." Then language or symbols became more universal and got specific enough that I can say, "eleven minus seven" and you know that's four. Additionally, you can also see four of something in your head since you know the relation of numbers to tangible physical things.

Suppose a bigger negative number is subtracted from a negative lower number. Like - 2 - -8 =?

this would change to -2 + 8 which equals 6

Can you take away negative numbers from normal numbers? Like: 9 - -1 = ?

You can think about this as subtracting a debt of $1, so if you have less debt you have more money in your pocket. 9 - -1 = 10. Or if you have learned that 2 negatives make a positive, 9 - -1 becomes 9+1 which is 10.

I'm practicing adding and subtracting mentally, I have no problem adding numbers quickly in my head but when it comes to subtracting it takes a little longer... What are some methods or tricks I can learn in order to subtract quickly without hesitation?

Here's a fast way to do 57 - 19. 19 is close to 20, so first do 57 - 20 to get 37, then add 1 back to get 38. Have a blessed, wonderful day!

Main content

Kindergarten

Course: Kindergarten > Unit 2

Lesson 1: What is addition? What is subtraction?

Intro to subtraction

Name: Intro to subtraction
Uploaded: 2014-04-25T19:24:36Z
Description: Sal talks about what it means to subtract. The examples he uses are 4-3 and 5-2.

Google Classroom

Sal talks about what it means to subtract. The examples he uses are 4-3 and 5-2. Created by Sal Khan.

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[Au]^79
Posted 9 years ago. Direct link to [Au]^79's post “What if the 2 numbers wer...”
What if the 2 numbers were switched? How can you even go below zero?
Button navigates to signup pageComment on [Au]^79's post “What if the 2 numbers wer...”
(55 votes)
Answer
- Blueberry
  Posted 4 years ago. Direct link to Blueberry's post “Below zero there would be...”
  Below zero there would be negative numbers
  Comment on Blueberry's post “Below zero there would be...”
  (4 votes)
imange77
Posted 6 years ago. Direct link to imange77's post “How far does negative num...”
How far does negative numbers go? Is it like normal numbers? Never ending?
Comment on imange77's post “How far does negative num...”
(18 votes)
- Devajsurya
  Posted 6 years ago. Direct link to Devajsurya's post “Yes, Negative numbers go...”
  Yes, Negative numbers go on forever just on the other side of the number line.
  Comment on Devajsurya's post “Yes, Negative numbers go...”
  (16 votes)
Hisha Harb
Posted 6 years ago. Direct link to Hisha Harb's post “Why subtraction has this ...”
Why subtraction has this (-) sign?
Comment on Hisha Harb's post “Why subtraction has this ...”
(10 votes)
- Michael Bedsaul
  Posted 6 years ago. Direct link to Michael Bedsaul's post “It is easier to use the (...”
  It is easier to use the (-) sign is stead of saying plus a negative.
  Comment on Michael Bedsaul's post “It is easier to use the (...”
  (5 votes)
NumerousSeven
Posted 5 years ago. Direct link to NumerousSeven's post “How would you represent n...”
How would you represent negative numbers?
Comment on NumerousSeven's post “How would you represent n...”
(12 votes)
- Deirdre Moore
  Posted 5 years ago. Direct link to Deirdre Moore's post “Negative numbers represen...”
  Negative numbers represent the distance in the opposite direction on the number line. The negative symbol can be seen as a subtraction sign, because 0 - 5= -5.
  Comment on Deirdre Moore's post “Negative numbers represen...”
  (8 votes)
MakaylaAnair
Posted 5 years ago. Direct link to MakaylaAnair's post “How do you write subtract...”
How do you write subtraction of negative numbers?? Like this: -2 - -1? It looks kinda weird to me.
Comment on MakaylaAnair's post “How do you write subtract...”
(5 votes)
- HarleyQuinn21345
  Posted 5 years ago. Direct link to HarleyQuinn21345's post “If you are talking about ...”
  If you are talking about subtracting a negative from a negative it would look like that but with parenthesis. -2-(-1). To write one negative number ,for example, if you solve 6-7 that would be equal to -1.
  Comment on HarleyQuinn21345's post “If you are talking about ...”
  (10 votes)
myzack001
Posted 7 years ago. Direct link to myzack001's post “what if you did 4-5? how ...”
what if you did 4-5? how would that even be possible? would it be 1?
(3 votes)
- Danny Foreman
  Posted 7 years ago. Direct link to Danny Foreman's post “That is a really good que...”
  That is a really good question. In reality you can't subtract more than what you have in the first place. For example, you can't start with 4 apples and then give away 5 of them.
  However, there are cases in which we can "take away" more than what we started with.
  Let's take the example above and think about it as steps. If you took 4 steps forward and then 5 steps backward, where would you be? You be 1 step behind where you started, which would be -1.
  Comment on Danny Foreman's post “That is a really good que...”
  (8 votes)
Reneasia Love
Posted 7 years ago. Direct link to Reneasia Love's post “I'm practicing adding and...”
I'm practicing adding and subtracting mentally, I have no problem adding numbers quickly in my head but when it comes to subtracting it takes a little longer... What are some methods or tricks I can learn in order to subtract quickly without hesitation?
Comment on Reneasia Love's post “I'm practicing adding and...”
(1 vote)
- Ian Pulizzotto
  Posted 7 years ago. Direct link to Ian Pulizzotto's post “Here's a fast way to do 5...”
  Here's a fast way to do 57 - 19.
  19 is close to 20, so first do 57 - 20 to get 37, then add 1 back to get 38.
  Have a blessed, wonderful day!
  Comment on Ian Pulizzotto's post “Here's a fast way to do 5...”
  (6 votes)
Joshua
Posted 7 years ago. Direct link to Joshua's post “who made subtraction? as ...”
who made subtraction? as like: who create the subtraction
(2 votes)
- jhawley2017
  Posted 7 years ago. Direct link to jhawley2017's post “No particular person crea...”
  No particular person created subtraction. Subtraction originated from the concept of removing an amount of something from a collection.
  
  Early man was able to grasp the concept of having a number of apples and then taking a certain number away and having less. Soon we understood that you can assign values or names to things
  
  ie: this is "one" apple. Everything after that just comes down to what was used to represent a certain number of something, is it "five?" "a grunt" or "cinco." Then language or symbols became more universal and got specific enough that I can say,
  
  "eleven minus seven" and you know that's four. Additionally, you can also see four of something in your head since you know the relation of numbers to tangible physical things.
  (4 votes)
billy wagay
Posted 8 years ago. Direct link to billy wagay's post “Suppose a bigger negative...”
Suppose a bigger negative number is subtracted from a negative lower number. Like - 2 - -8 =?
(2 votes)
- DannyIam8
  Posted 8 years ago. Direct link to DannyIam8's post “this would change to -2 +...”
  this would change to -2 + 8 which equals 6
  Comment on DannyIam8's post “this would change to -2 +...”
  (3 votes)
dcruz135
Posted 7 years ago. Direct link to dcruz135's post “Can you take away negativ...”
Can you take away negative numbers from normal numbers? Like: 9 - -1 = ?
Button navigates to signup pageButton navigates to signup page
(2 votes)
Answer
- Mrs. Gardner
  Posted 7 years ago. Direct link to Mrs. Gardner's post “You can think about this ...”
  You can think about this as subtracting a debt of $1, so if you have less debt you have more money in your pocket. 9 - -1 = 10.
  Or if you have learned that 2 negatives make a positive, 9 - -1 becomes 9+1 which is 10.
  Comment on Mrs. Gardner's post “You can think about this ...”
  (2 votes)

Video transcript

Voiceover:Let's explore what it means to subtract numbers. So let's say that I want to figure out what 4, what 4 minus 3 is. 4 minus 3. So one way to think about this, is you start with 4 objects. And so let me just draw 4 objects. So there I have 1, 2, 3, and 4. And when I ... So this is the 4 objects right over here. And when I say minus 3, or if I'm going to subtract 3 from the 4, one way to think about it is, I'm going to take 3 of these 4 objects away. So let's do that. So I'm going to take away 1, I'm going to take away 2, and I'm going to take away 3. Notice, I took away 1, 2, 3 objects. So how many do I have leftover? Well, if I start with 4 and I take away 3, I subtract 3, 4 minus 3, I am left with, I am left with, 1 object, right over here. So 4 minus 3 is equal to, is equal to 1. Fascinating. Let's do another one of these. Let's figure out what 5, what 5, what 5 minus 2 is. And let's write it this way. Let's say we want to figure out something, some question mark, some question mark ... Actually, let me just clear this out. I'll just do it right over here, actually. So let's say we have some question mark. So there's some unknown number right over here. So I'll just put a question mark over here. And we say that unknown number is equal to, is equal to 5, 5 minus 2. Minus 2. Minus 2. So what is this going to be? Well let's visualize it. This means I have 5 things and I'm going to take away 2 of them and this is going to be what I have leftover after I start with 5 and take away 2. So I have 1, 2, 3, 4, 5 things. Now I am going to take away 2 of them. So I'm going to take away 1 and 2. So I took away 1, 2 objects. So how many do I have leftover? Well, I have leftover these, these ... Let me do this in a different color. I have leftover these purple things right over here. So how many is that? How many do I have leftover? Well, I have leftover 1, 2, 3 of my original 5. So something is equal is 5 minus 2. That something is 3. 3 is equal to 5 minus 2. Let me just replace this with a 3. So we see that 3 ... Actually, let me do the 3 in the same color as this green. So we see that 3, 3 is equal to 5 minus 2 or we could say that 5 minus 2 is equal to 3. Either way.