Adding/Subtracting negative numbers

[f22raptor3425]

The people that dislike this are really dumb\stupid!!!

[f22raptor3425]

@f22raptor3425 Yeah! Your totally right man!

[f22raptor3425]

@f22raptor3425 Of course i'm right!!

[ManWithNoPlanYet]

are you the smartest man on earth, if not, you should be

[Catasaurusrex1]

thxx:)

[BelcantoLola]

Thank You!

[billfromtopgun]

5:21 The 'negative signs cancel out'. Pretty poor explanation...

[Starshooter662]

This video was grate after i Finished i understood this concept perfectly.

[MrMGD92]

An easiar way to understand this is to remember you go from a negatvie to a positive you start with negative numbers then go up so 0123 and so on is going up and 0-1-2-3-4 is going down.

[Zinkchaching]

wow i am in high school and i need to review this, i am so ashamed lol

[Hprulez19]

the HP part is Harry Potter so Harry Potter rulez the 19 is just there beacause i wantt it there

[Hprulez19]

i like this, really i do!!!! ;D

[pumpkinpie102508]

OMG!! this is wonderful i have always had a problem with these stupid intergers!!!! ever since 6th grade i could NEVER do them!!! I finaly understand thats to you! i think i did this one right, not sure: (-3) + (-4) - (-5) - (+6) = -8. Correct me if i'm wrong! i LOVE learning from my mistakes,and fixing them so i can be better at the things i misunderstand! thanks - Jenna

[fiercecandy]

@pumpkinpie102508 your answer is wrong, the answer is actually +3

[IMBIue]

@fiercecandy what you talking about she got it right...

[MultiGameinformers]

what the programe you use called

[TheTakealeap]

great video & great explanation. made things very clear, thanks :)

[MegaPinky102]

Thanks this is very helpful!!!!!!

[hanasimons]

I seeeee :/

[hanasimons]

Sweet line :3

[Calaleb]

Thank you so much. I'm only watching this because it's homework. Anyways, this still makes sense to me:)

[body4me2c]

at 6:31 or 6:32 he said that he's going to give us a bunch of prombles..... please so down!!?!?!??1!

[body4me2c]

this guy is so helpful imaen like he just basicly just did my homework for me

[body4me2c]

i am so lost ...waiit i get it now ......hold try to copy this down.....got it wow you made my life better thank you so much

[BensxProductions]

thanks its very helpful!!!!!!!!

[complains2much]

I really try to understand this stuff when I read it from the books, but that never works, but the way you put it makes it so much more simple. Please keep putting out videos they really work.

[usuc77]

ZEROOOOO PAIRSSSS!!!!!!!!!!

[jrobertson006]

Thanks this helped so much!!!!!

[ronaldofreekicked]

I need much more help than this.

Any suggestions?

[keepitreal006]

thnx for hellping me understand my homework ;]

great job

[teddybearjoe2111]

Clearly, has alot of time on his hands. But, we are so greatful for all your hard work helping us to become smarter in math...

[tacos50000]

what program does he use?

[MultiDrebrown]

thank u khanacademy my son is doing great in school cause of u he said thanks

[blueEyelashes400]

hello i have a jingle that my teacher taught us "same SIGNS add and keep DIFFERENT signs SUBTRACT take the sign of the higher value then it will be exact " THUMBS UP IF HELPFUL 2 U

[blueEyelashes400]

@blueEyelashes400 thats 4 adding

[lesanne2]

Thank you.

[C00kieMonster9]

Im only in seventh grade....but this really helps! Thank you!!

[thelastnameiwanted]

@C00kieMonster9 if only I had video's like this in seventh grade

[Gallo20002000]

Do the of 2-(-3) without the simplification to see how it really works!!!! On the ruler (numbered)

[EzzySally23]

Finally, I learned how to add and sub negative numbers. Thank you!

[halfadozenshorts]

Like if u go to CGS and ur watching this video from tate short

[barnii007]

@halfadozenshorts did you whatch the whole thing? :P from alec

[96malvarado]

easy and simple (:

[michaelhunter03]

sal is great



[michaelhunter03]

your great

[mrbooni02]

thanks

[Oli9779]

hey man you are incredible! I have my end of year exams on Monday and there really important coz next year I decide what Im taking for G.C.S.E.! oooo scary! But you have helped me more than my teacher at school! I will let you know how I get on in the exams.

KEEP DOING WHAT YOU DO BEST! ( MATHSSS!)

[DISCOBISQIT]

I have a question, what is -6 - (-2) ? why is the -2 in parenthesis?

[aarondude0]

Im in university and i still forget dealing with negative numbers :P

[bananapuff4667]

OMG! This helped moi alot! thnxs Sal!

[mastershake589]

You are all a bunch of dickbutts, this is easy.

[boysjoy3]

thanks a lot Sal

[boysjoy3]

thanks a lot Sal you help me sooooo much

[CocoMunky]

i have to say thank you a million times over. i never understood negatives and it was frustrating me to tears, literally! but that number line with the examples really helped me understand it in a way i was unable to before. thank you so much!

[tirazab]

@marcoaranas yes a neg-neg= pos

[tirazab]

Wow this helps!!!!!!

[KayShoshana92]

Thankss!!

[LevelHeadedGaming]

Thank you!

[MyOverflow]

@FredMayX2 Well since that comment was made, I had finished it. I'm not a second year math and computer science major breezing through all of my math classes. Trust me, Sal's videos are truly life savers.

[251brenda]

lol



[TheREV504]

DO THIS RULE APPLY TO TEMPETURE EX. 34 -(-20) = IS THE ANSWER 54

[jdbmin]

its ok it takes time to know it

[kcj1993]

This makes absolutely no sense to me at all. :(

[armanfazli]

Thank you with the number line it helped me get my homework done. Thank You!!!

[jimmytube717]

does 5 + - 6 = -1 ?

[Hisdaef]

@jimmytube717 Correct!

[XpeanutttX]

Thnx, this is really helpful :)

[JamalMohamed1967]

thanks



[JamalMohamed1967]

thanks



[dangerblad]

thanks ur good

the books r kinda shit ;)

[marcoaranas]

so is this it neg-neg=pos? 

[96arun]

then how about finding 100-150 Mr.Khann!!!!!! draw a number line of 150 units long on the left and 100 units on the right and find the answer...... it is a too cumbersome method!!!!! just teach children simply "if you want to subtract a larger number from a small number just find the different and put a negative sign" very simple method!!!

[jstarks123]

@96arun ....children need to understand "why" something works. Simply having them memorize a rule is not helping them, because they will forget the rule eventually. The number line is a great tool because it teaches the concept. Once kids grasp the concept, they won't need to use the number line anymore.

[carolinabonita1]

@vickiomindyb - He explains during 7:50

[BusterPosey211]

Hello, Salman Khan. I'm 12 years old and I'm wondering what's your opinion on Kumon math?

[Yallno22]

Is it so that subtracting, two negative,which is to move right, is adding, relative to

positive numbers, and subtracting two positives, which is to move to the left, is adding, relative to negative numbers. Like this -7 - -2= add right move -5

or +7 - +2= add left move +5 In both examples, your subtracting, but also adding.

[yasuodances]

Thanks for the videos.

Helps out a lot.

[CelebsRStupid]

download this for free at grabtube.com

[kabz63]

thanks dis helped me a lot ur da best

[shanadono]

I totally blew up this site with comments! Yikers! Sorry Twitter and Facebook!

[shanadono]

I forgot the link to my video. If you click my name it's the first video that pops up. Well, it's not a pop up, it's actually really helpful. Popups are never helpful!

[shanadono]

my calculus professor told me that calculus students often get caught up in the algebra. I think the same is true for algebra students and arithmetic (negatives!) I invented a tool I hope you check out. It takes the mystery out of negatives by using absolute value...

[kaykushwaha]

Thanks so much. My ten year old now gets it!

[CaloKitty]

It's not negative numbers,but niggertive numbers!!

NEGATIVE=BAD NIGGERTIVE=GOOD!!!!!!!

[everthangjustin]

@CaloKitty N ur white trash-i-tive!

Sucka

[shanadono]

Sorry about not writing any text in my comment! Your video is great. As a math teacher, the biggest ptoblem my kids stil have is with negative numbers. Try solving for y in "y + 22x = 5x - 7" if you don't know what "5 - 22" is! I developed the tool I posted (the ZeroSum ruler) to help my students. I was hoping you may check it out. We'll get kids over this hurdle!

[piasmom]

Helped my daughter while we were on vacation. Thank you!

[Dexduzdiz]

why do the negatives cancel out?? i dont get it

[shanadono]

@Dexduzdiz did you ever get your answer as to why negatives cancel out? If you didn't, I thought I'd answer. In math, as you may know, anytime one thing is right next to another, it means "multiply". You probably know this with "2x" meaning "two times x". But this is also true for 2- -2. the - - literally means "- times -", which is +.

[shanadono]

@Dexduzdiz What's also true is that any netive sign is really a "-1" in disguise. So "-2x" is really "-1 times 2 times x". Mathematicians are lazy so use shorthand for EVERYTHING.

[sexy19081995]

dis guy is rubbish.....i can teach beta....

[cheongdaphne]

@sexy19081995 dont be so mean..he rocks!

[sexy19081995]

heheh kiddin....sorry

[sexy19081995]

but i didnt undastand

[g37muflih]

please help me on solving square root of larger numbers

[SantosMarKaitlyn]

thank you!I really needed help on this.

[luis21414]

these problem is very easy

[dewalt607]

thx a lot this is amazing!!!! it just cant get any simpler! i have found the answer to my math help ! awesome!!!!!!!1

[nilved33]

thank you khan :)

[theredone09]

it's a linier math tabel as long as u remember going left was - and right was+ then u would see nubers go on forever

[theredone09]

the thing is below zero is a way of saying really really low and is the only way that we humans can identify it because our number line only goes to zero but in physics the number line goes down forever so -50 is our way of saying really low to a point of our understanding below zero exists with our with out humans

[Lazerwolf27]

Math will be math no matter where in the universe you go...because of man, and it will be just as flawed here as it will a million light years away. The only reason math works the way it does is because it's what's been the norm for a long time, so it's accepted that 1+ 1=2...As for your borrowing of money, once again like I've said you can't get what I don't have. That's how America is in the mess it's in now....because banks weren't lending money, they were lending numbers.

[Lazerwolf27]

People understand "below zero" because that's how it's always been taught to them. Math is a flawed system, and the answer as to why that is, is simple because math was brought about by mankind...and mankind is flawed, therefore math is flawed. As for your -2 apples and debt comment, it's still false. you can't be negative anything....because it simply doesn't exist. Yes you might owe someone 2 apples but your not negative 2 apples because you can't have less then zero.

[PsionicStormed]

your sum is awesum!

[Lazerwolf27]

Negative numbers are not real. Therefore anything that uses negative numbers is false...making math false. In reality you can't have one and subtract three because well you can't have any less then zero....example....I'll use your example. You have one apple and someone takes three apples....it can't happen because you don't have three apples to give....

[krazzy]

Dude... I love you.

But, Why would these numbers be used then? So kids fail algebra? Or maybe im an idiot.

[Lazerwolf27]

Who knows why someone decided that negative numbers should exist....to confuse the rest of us maybe

[tubolclorosis21]

wow ur soooooooo smart ^^

[yl358]

@Lazerwolf27 That may be true, but I'll offer a counterexample. You can be 5 degrees below zero, and when you go down 5 degrees, you are now at 10 degrees below zero. The math here is: -5 - 5 = -10. Negative numbers can be real.

[Lazerwolf27]

@yl358 I see what you are trying to say however, all you have done in take a number associated with money and made it into a number associated with temp. It still holds true in this case too....Take it like this, Before science was into all of these elements that freeze bellow zero, there was freezing point for water. This is a substance everyone in the world knew about and it's the base of how we measure Temp. Scientists back in the day said Water freezes at 0 Degrees Celsius and boils at

[Lazerwolf27]

@yl358 100 Degrees Celsius. That's what they came up with at the time because they didn't know anything else could freeze below that number.....which to be honest numbers are just a made up thing to start with some person said that this symbol 3 would equal what we now know at three. Back to my point though... Say theres a universe where Methane is like water to us, it freezes at -296.5 Degrees F....so that would be there zero...or 32 F...I still stand to my point that nothing can be lower then

[Lazerwolf27]

@yl358 0 in nature....man came up with the symbols that equal what we now know today as numbers, and assigned a set amount for those numbers.... like i've said if you have 0 of anything in the actual physical world you can't have any less, and the same kind of applies for water and such ice isn't going to get any more ice like just because it's -5 degrees.... I'm not a scientist of any sort and i'm sure theres some one out there that can school me on this subject, till then i'll remain ignorant.

[6507shaho]

What could 20 + -10 = ???

[Xxclusivexx999]

wouldn't that be 30???

[MegaShadowslayer]

...

[MegaShadowslayer]

Then What Is A Positive+ A negative? O.o

[spitfire865]

It also is a negative.

[Y0UNG3BL00D730]

i love how he says hope u have fun!!!

[alternit]

is there any way to show subtracting a negative number on the number line?

Say 5 - -7?

[fireteambrovo]

@alternit Yes, the negatives cancel out an turn positive. SO - 5 - - 7 = 5 + + 7 = 12. On number line it would you would start at 5, go to the right 7 times. 

[DirtyWarry]

@alternit I do it like this, 5-(-7)

[petlover345]

Your Smart Thanks This Helped!!!!!!! Great Jobb :))

[MissCongeniality2020]

This is the reason why I got into AP Math! Thank you khan academy!

[AUTubeN22]

this is like heavy dumbell weights for my brain, thanks! its easy to remember (perentheses) the word not the spelling sorry! my parents. they come first before me!

[auxentiu]

kind of confusing.....but I knda get it.....kinda.

[OrlandogPsy]

- - is + (example: 3- -3=?) Answer: 3+3 = 6

[invaderultima]

sorry for double posting but my teacher says to same, change, switch.

basically if your subtracting rewrite to addition and if it is the same signs than you add and if they're diffrent subtract.

[invaderultima]

OMG thanks im in 7th grade and we have a test tomorrow and I can't wait untill i pass! (hopefully!)

[AquaCatClaws]

oh GOD this is good ! the best i tell u ! thx ! and im in 7th too and i always hv to look in my txt book again to do my problems --not anymooooorreee !!! :-)

[invaderultima]

lol

[Lilmissnaughtylove]

i still dont get it

[Wafflesmart]

a negative number - a positive number is the same as a negative number + a negative number.

A positive number + a negative number is the same as a positive number - a negative number. When you mix negative numbers with positive numbers it just gets reversed.

But.

A negative number + a negative number just equels a smaller number.

So on so on. But My definition is probobly even more confusing than His.

[tmic507]

oh basicly keep the sign of the bigger number

[NickDirecter]

Gret vid!

[CrackedVersion99]

THanks man ! i completly understand it now

[superjtrdr]

The important point is to start off by plotting everything on the line. If you are adding you go to the right if you are subtracting you go to the left.

The only exception is when 2 minus signs are right next to each other. In that situation you replace the 2 minus signs with a plus sign. Which means you go to the right (adding).

[Arceus2000]

An easy way to do the problems where you are subtracting two positives and they are going to come out as negative numbers is this:

Switch the numbers around, subtract, and then make the number you got a negative number. That's the answer to the original equation.

Example: 9 - 16

Switch and subtract:

16 - 9 = 7

Change to a negative:

16 - 9 = -7

Switch back:

9 - 16 = -7

There you go!

[MyOverflow]

Haha, you know what Sal?

I have a 180 page notebook with me right now.

I'm going through all of your videos from Pre-Algebra to Calculus (and beyond, if possible) and using 1 page at a time for each topic.

Side 1 of page: Explanation and examples.

Side 2 of page: Problems/Examples found online.

Hopefully, by filling up this notebook, I'll be able to go through all the math in college like it's nothing. :)

[ReleaseTheLions]

Same here.

[HeyyHuda]

@MyOverflow smart!! i have an exam at 10 and im watching all his vids right now lol

[HumanTargetAus]

@MyOverflow I see that your comment was left 1 year ago, have you made it to college yet?

[MyOverflow]

@HumanTargetAus Yep, I am a second year Math and Computer Science major with a 3.8 GPA. I should be 21 with two Master's degrees, because I started college when I was 16.

[HumanTargetAus]

@MyOverflow Wow, thats a good effort mate! Especially to be doing Computer and Math science! How did you Manage to start college at 16? and what are is the scale of grades in america? In australia the grade scale is 1-7 (4 is a pass). I am at college studying Mechanical and Materials engineering and Physics.

Ill send you a friend invite because it seems that we both like science and math and even carl sagan it seems!`

[MyOverflow]

@HumanTargetAus Here in America, the grading scale is 1-4, where each one is basically 25%, so 3.8 * 25% is a 95%-96% average. I think my average is so high because some of the general required classes (like history, literature, etc) are curved by the instructors for non-majors (there are three types of classes: classes for majors in that subject, classes for non-majors, and classes advanced enough that you must be a major in that subject), and so my curved grade always had me above a 100%.

[MyOverflow]

@HumanTargetAus Also, I started college when I was 16 because I got my GED (General Education Development) diploma, which is high school equivalency, and scored high enough on my ACT to get 2 years free at the community college I'm currently attending.

Now, because of my grades at this college, when I transfer to a 4 year university, I'm going to get a couple more scholarships because I'm both a math and computer science major, and because of my GPA.

[FaberCastellFilms]

Onte, fun nun camiño ata o lago. Logo veu un imortal assassino coelhos e bateu-me no chan.

[StarsofSlash]

for little children///

[yeseyyesey]

hmm.......i had to play the vid over a few times becuz i wasn't paying attention(to busy peeling skin) but u explained it better than my teacher! i might get a A+ tomorrow(also a lollipop! ^-^)

[DSMASTER911]

omG I HAVE A TEST TOMOROW

AND U HELPED ME UDERSTEAND THIS !!

THANK U

DANKE SHUN

GRACIA

GRAZIE

[zarnos]

How would you work out 73

- 84

?? Ie Whats the process?  Cheers

[circlesarecrazy]

73 - 84 = -11

[IdidURmom2]

awesome

[Moriahthehedgehog]

OMG This Video Helped Understand What Negative Numbers Are I've Been Having Problems With These In School And With My Getting Homeschooled They Seem Easier

Thank You Im Faving

[ceomeye]

very nice. Better than my saturday class teacher who spent an hour on this...

watch?v=rO8JWbG6bVw

[yoonl12]

Thank you ^-^

[JJandKKole]

Thanks so much for setting up this site. As homeschoolers, we are always looking for a new way to learn an often difficult subject. My girls found this very helpful. I have a question--you mentioned modules. Is there a text or work book this is based from where we can find more problems to practice these math concepts?

[vickiormindyb]

I don't understand: Why do the negatives cancel each other out?

Will I be able to do the problems if I don't know why they do?

[khanacademy]

Subtraction is like saying "not" when speaking. "I am not going to the movie" means that you will not go to the movie.

"I am not not going to the movie" means that you will go to the movie.

In language and in math, double-negative cancel out.  If I "take away" negative 5 dollars from you, I am giving you $5.

[AquaCatClaws]

wooow !

u could possibly be dubbed " Mu'aallim "

thx sal !

[sexy19081995]

your intelligent dude

[GodDude2]

The way my teachers said it was that subtracting a negative is like adding a positive.

[vickiormindyb]

I always have trouble learning this, because my seventh grade teacher had to stop so many times and yell at this kid, who kept causing trouble in class.

It was like that the whole year. Now every time I'm trying to learn this, I can hear the "ghost" of that teacher's voice yelling at that kid.

It's getting easier to shut out the memory, but it's still hard to keep it away.

[rj216907]

Great Teacher teaching something very difficult to master.

[thatboig0off]

hey nice job in teaching this i learn it more then from the school that i go to thats is sopose to be a magnet school

[FiLcHiQ]

Thank you sir for this presentation that u posted this has really helped me alot.I'm studying here in London,U.K but I'm originally from the Philippines.I dont really understand the way they teach here.Thank you once again.God Bless

[michaelmiao]

great teacher!

[odeliarios]

thanks!

[osvaldope]

great video