# Inverse property of addition | Arithmetic properties | Pre-Algebra | Khan Academy

Let’s say that we have the
the number 5 to get to 0? And you might already know
this, but I’ll just draw it out. So let’s say we have a
number line right over here. And 0 is sitting
right over there. And we are already
sitting here at 5. So to go from 5 to 0, we have
to go five spaces to the left. And if we’re going five
spaces to the left, that means that we
5 right here, then that is going
to get us back to 0. That is going to get us
back right over here to 0. And you probably
already knew this. And this is a pretty maybe
common sense thing right here. But there’s a fancy word for
I’ll just write it down. I think it’s kind of
ridiculous that it’s given such a fancy word
for such a simple idea– additive inverse property. And it’s just the idea
inverse of the number, which is what most people call
the negative of the number– if you add the negative of
the number to your number, you’re going to get back
to 0 because they have the same size, you
could view it that way. They both have a magnitude
of 5, but this is going five to the right and then you’re
going five back to the left. Similarly, if you started at–
let me draw another number line right over here– if you
started at negative 3. If you’re starting right
over here at negative 3, so you’ve already moved
three spaces to the left, and someone says, well what
do I have to add to negative 3 to get back to 0? Well, I have to move three
spaces to the right now. And three spaces to the right
is in the positive direction. So I have to add positive 3. So if I add positive 3 to
negative 3, I will get 0. So in general, if I have any
number– if I have 1,725,314 and I say, what do I need to
add to this to get back to 0? Well, I have to essentially
go in the opposite direction. I have to go in the
leftwards direction. So I’m going to subtract
the same amount. Or I could say, I’m going
negative version of it. So this is going to be
the same thing as adding negative 1,725,314 and
that’ll just get me back to 0. Similarly, if I say, what number
do I have to add to negative 7 to get to 0? Well, if I’m already at negative
7, I have to go 7 to the right so I have to add positive 7. And this is going
to be equal to 0. And this all comes
from the general idea 5 plus negative 5, 5
plus the negative of 5, or 5 plus the
additive inverse of 5, you can just view this as
another way of 5 minus 5. And if you have
five of something, and you take away five, you’ve
learned many, many years ago that that is just
going to get you to 0.

## 16 thoughts on “Inverse property of addition | Arithmetic properties | Pre-Algebra | Khan Academy”

1. @Twinsfan36
The result is the same. And you'd maybe think: what's the difference?
But this is actually used. Some CPUs/micro controllers don't have a separate "subtract" function (because every additional function needs space on the chip). So to subtract you have to add the inverse.

2. shit im a 4th grader and already learning pre algerbra 0_0

3. @mikestertech101 i learned it when i was in 3rd. Trust me, it pays off in middle school because if you werent paying attention in class you probably already know it.

4. @jonjonjon1370 Thanks for the tip ðŸ˜€

5. @mikestertech101 no problem, btw- i checked out ur minecraft videos and theyre great. Im subscribing to you!

6. @jonjonjon1370 Hey thanks a bunch ðŸ™‚
Nice to hear something like that from someone i dont even know !

7. I love this. It was tickling my brain.

8. the things the teacher says are gibberish, but you say it kid freindly ðŸ˜€

9. I'm in seventh grade and I'm learning this now?!

10. Dope stuff breh, fire bars on this one ðŸ”¥ðŸ”¥ðŸ”¥

11. extremely helpful.Â  teaching algebra for the first time.Â  DOING algebra for the first time.Â  learning curve has G forces!

12. I kinda get this video

13. Proof math can be simple!

14. I'm in 5th grade and I'm learning it now and i get thr video

15. Sub plz

16. our teacher gave us a worksheet where we had to work with this.None of us students knew what i was and when we asked the teacher, turns out he didn't know either and told us to search it up

AND HERE I AM