Introduction to interest

[NoughNeaux]

7:40 - Why do you square "(1.1)" ?

[iNinjaNotes]

@NoughNeaux Each year you pay 10% of interest on the NEW balance. So in year one you owe $100 + 10% which is $100 * 1.1 = $110 (since you owe the principal loan and interest). The reason he squares 1.1 is because he is trying to shorten the expression. For instance, in year 4 you would owe...$100 x 1.1 x1.1 x1.1 x1.1 = $146. But instead you can shorten that expression to $100 (1.1) to the power of 4. Since there are four 1.1's

[Joeses15]

@MrDevin666 1.1 is the same as 110% but in decimal form.

[MrDevin666]

This stuff is simple, BUT I have one question to ask for an answer. At 7:41 he changed it from 110 + 10%(110) to 110(1.1), where does that 1.1 come from?

[iNinjaNotes]

@MrDevin666 1.1 is the same as 10% interest rate on top of your initial investment which is 100%, 110% is equal to 1.1.

[MrDevin666]

@iNinjaNotes Yeah thanks for the reply, but I got it. He said that you undistribute the 110, which made no sense, he meant factor out 110.

[LNasterio]

OMFG ... we spend like 2x1hour lectrue on this.

and did not make any sense at all.

yet you spend 10mins and I totally got it...

[Coogify]

lol we've learned this in 8th grade honors

[delameu]

my interest in this video is equal to 0

[submissivegirl12]

thanks sal

[Madidog123]

In the comments: To. Much. Arguing. Its an "introduction to interest" -- math. Please, don't pull in religion. If you want to argue about religion, go to a religious based video. If you want to argue about math, stay here. But for goodness sakes, dont mix the two! There is a time and a place -- it is not here, not now.

[RealFngDeal]

@Madidog123 No reason one can't, don't like it; don't read it.

[Madidog123]

@RealFngDeal hehe, I didn't particularly read it. I just scrolled through ^^;

[RealFngDeal]

@Madidog123 Ahh cursorily, understandable, If you do read through it; you'll see I'm not particularly even talking on the subject that you described. In particular I'm speaking of bigotry.

[Madidog123]

@RealFngDeal my apologies, then. Sorry for sounding a little stuck up (or whatever I must have sounded like...) I was having a bad day, and got aggravated... Sorry again -_-||||

[toon2claes2]

is this for stupid people?

[Gielinorian]

Someone said something about murder and how it can be considered "right". Some people want to murder people, to them it's right. That's how it's right, by someone saying it's right. You said it's wrong so it's wrong to you, I say it's right (metaphorically) so it's right to me.

There's no right and there's no wrong, get over it.

[AllYouNeed1sLove]

I want to thank you for what yo do. I am a middle school math teacher, and I stole your "rent on money" metaphor for my simple interest lesson. Keep the math videos coming.

[0Umbrakinetic0]

Where's "Moral side to Murder"?

[nodreale]

You should borrow money and buy a better video capture program.

[ragenFOX]

interest is bad.

[beehivecity]

math isnt real its just numbers when god made earth there were no numbers

[thybuilder]

@beehivecity Maybe god isnt real ? At least math is logic.

[beehivecity]

@thybuilder Hm, interesting. However, God has been proven real by math

[thybuilder]

@beehivecity God ? As in the dude u leanrt about in sunday school ? Can I have the link to a website that proves its existance ?

[beehivecity]

@thybuilder wikipedia

[thybuilder]

@beehivecity HAHAHAHA. I ask for website that proves it's existance you you mention Wikipedia ? Did you know that wikipedia can be written by anyone, did you also knew that that is biased ?

[beehivecity]

@thybuilder Interesting theory, however Wikipedia is not biased and God is factually real. Checkmate

[RealFngDeal]

@thybuilder Humans are bias, going by your logic anything you hear or read could then not be taken with any validity. Sad excistence to live if you ask me; also wiki has already been proven to be as factual as brittanica. Yes it can be edited by anyone however there are paid editors to make sure things are valid.. and in some cases valid to what contemporary logic thinks.

[thybuilder]

@RealFngDeal Who says those editors are not "biased" ?

Not necessarily anything, but when it comes to proving gods existance thru the internet, there's nothing more appealing than cynicism.

[RealFngDeal]

@thybuilder Like I just said. HUMANS ARE BIAS, in a nutshell you'll believe what you want and be incredulous towards the rest. Being anecodtal about who is bias is obtuse as pretty much everyone is bias in some way.

[thybuilder]

@RealFngDeal Of course I believe in what I want, don't you ? I for one choose to believe in something that has enough proof to sustain it's argument.

[RealFngDeal]

@thybuilder There is validity both ways. You're palpably demonstrating a euphemistic attitude and trying to be condensending about it, That's fine and can typically be found amongst humans with concrete cognitive thinking. But I beseech you to learn some tolerance and not be so hasty to plagiarize someones dignity just because their beliefs are different, you'd think mankind would have learned through thousands of years of bigotry in history but I guess nobody was listening the first time.

[BillyBobTS]

@RealFngDeal Well said.

[thybuilder]

@RealFngDeal Since when, does asking for concrete proof become a type of ignorance towards religion ?

[RealFngDeal]

@thybuilder Never said ignorance.

[thybuilder]

@RealFngDeal Tolerance and ignorance are sisters in this context. But as you wish, asking for decent, plausible and universal arguments to fundament an argument does not make someone "intolerant".

[RealFngDeal]

@thybuilder Equivocal definition I say. To disambiguate, asking that question does not make someone intolerant. What does is using statements like "is that what they teach you in sunday school" which is a palpable means of demeaning it, and saying; "At least math is logic." in conjunction with "god isn't real" is also an attempt to demean it. Do not play coy with me, what you were doing was the exact opposite of tolerance. The satire in the topic of bias, prejudice shows.

[thybuilder]

@RealFngDeal Math is logic, the existance of god is refutable, and you learn about your maker in sunday school. Those my friend are facts.

[RealFngDeal]

@thybuilder Ahh the interminable condescending. It's almost as if i've been replying to a brick wall. On the basis of math though, according to that "logic" there could be a supreme being. But that's besides MY point that clearly seems to be nebulous to your comprehension.

[someguythatwantsutub]

Now we need to get rid of the Harvard comments :)

[kyoogoo]

my mind is boggled.

[thybuilder]

I gotta agree this is basic school education, do you learn this in collge americans ?

[theflaminggrunts]

@thybuilder Umadbro?

[MrBWB]

@thybuilder Some learn in "basic" school, others don't. My schools didn't offer this stuff, and I didn't learn it formally until college. But my dad taught it to me and most people learn it on their own. I imagine private schools and better public schools would cover this stuff, but the poorer public schools don't. The education system I grew up in valued things like calculus and chemistry, and had almost no classes of practical use. -an American.

[ssbfan99]

this is the first time ive ever seen something educational on the education section on the youtube home

[TankOwnsAll]

@tito1894 I totally understand what you're saying man! It's pitiful how stupid the average american society is. Haha

[MrZaheermir]

good to know

[ragenFOX]

there is a reason why its a sin in all Abraham religions.

[tyeon95]

BRING BACK HARVARD!

[Zander000000]

Bot? 250k views, front page, only 287 likes and 17 dislike, only 123 comments? what the ****

[Zander000000]

@Zander000000 only 2 video responses and reactions as well?

[xxXArmaniEXxx]

Why didn't I saw this video before taking out student loans :(

[TankOwnsAll]

@diedie111590.. In America people also know the difference between you're and your...I'm from America, thanks for trying to Rep us, but that was a fail..

[tito1894]

@TankOwnsAll I'm from America, and the percentage of Americans that know the difference between your and you're is low.

[Markurn]

in europe we learn something like this in early middle school.. wtf america ..ur all so stupid!

[diedie111590]

@Markurn In America people know how to type with correct grammar and know how to spell "your". You really look stupid yourself for commenting on this video.

[Markurn]

@diedie111590 stfu u gay dumb fuck

[Markurn]

@diedie111590 fucking grammar nazi

[FlaggedFTW]

@Markurn Because swearing makes you seem smarter. My IQ is 135. What's yours? Europeans, so arrogant and envious.

[diedie111590]

@Markurn Lol youmadbro?

[Markurn]

@diedie111590 lol

[Aelfredus26]

The Harvard video will be back. You guys just wait...

[11danyboy11]

whats up with all the Harvard thing? can someone explain?

[noldi123]

@11danyboy11 there was a harvard video about law on the front page for many weeks and now its finally replaced by this. everybody pretty much knew that harvard bought that spot on the front page just to advertize their university (it is college applications season), even though its almost impossible to get in. they love collecting application fees. 30000+ applicants at $50-70 an application. mucho dinero

[CreedCroud]

Suck it Harvard! :D

[IdaWasHere94]

Haha I kept thinking YouTube was messed up with that Harvard video being on the home page.

[iSynesis]

@khanacademy, Your Program has made it too CCiSD, In Houston Texas. Congrats, Its AWESOME! :) I Like listening to Your Vid's rather than dumb Lectures!

[kphantomkk]

My god! I can't draw a straight line with my mouse, how the hell does he write with it!

[Kapetozzo]

@kphantomkk he's probably using a tablet, and by tablet i mean the real shit like wacom bamboo

[qseanx]

google whoisgoddotorg

[Vinzix]

Now this is trolling the frontpage, yay.

[Microwavish]

math is gay

[vesji]

@Microwavish You are a moron, sorry.

[Microwavish]

@vesji name one person who knows math who isnt gay

[vesji]

@Microwavish You ( I hope )

[MrBiace]

@Microwavish WTF?

[mafleeted]

@Microwavish LOL

[lolusuckblackdick]

@Microwavish lmao fucking art students these days

[AmdAtiForever]

@Microwavish

Knowledge is never gay.

[xAvodinhx]

@diedie111590 lol? The US dollar sign has two lines through it. It's just simpler to put 1. Either is acceptable, the fact that you're ignorant enough to say it only has 1 line shows you have no education whatsoever.

[mafleeted]

LOL

[TheKoper22]

i learned this in my 7th grade math class...

[MatiKase]

This is just funny how people think that we in Estonia are not very smart xD But now I can tell you ... If you didn`t know this you are actually not very smart, And that´s the truth :)

[jonkke92]

@MatiKase nice grammar dummy

[MatiKase]

@jonkke92 :D now try to write me something in perfect estonian ! döööö...

[cliffrdwood]

Messianic  Jews

[commanderflames]

Wow I never thought about it this way I was so blind thank you for posting this up. I don't care about the harvard video so shutup you idiots. And for last i love those messy commentary videos like this it makes sense and since its a mess it makes me understand more for some reason.

[Ameritaku]

Khan Academy is like making a school from "for Dummies" books... which is extremely effective, logical, and interesting. He makes education more personal.

[Kimjongil3000]

Hooray! The Harvard video is gone!

[imcriticizer]

GOD BLESS THE INTERNET! NO MORE DYING PASSENGERS HIT BY DRIVERS WITH NO CAR INSURANCES DILEMMAS!!

[Disturbed763]

REJOICE FOR HARVARD NO LONGER CONTROLS YOUTUBE.

[BostonMtnSyndicate]

Fuck yeah! Putin is gone! We brought down the IRON CURTAIN! That was very annoying Harvard.

[20Marian796]

hookup tonight bit.ly\qfKLmR

[vickiormindyb]

Donald Trump filed bankruptcy in the late 80's when, according to my friend who worked on Wall Street in the late 80's, you could make money easier than falling off a log.

My friend's co-worker claimed he knew this when he was 4 years old, like I'm supposed to believe him just b/c that's what he said. He better go find someone dumber than that, b/c I'm not it.

[PleaseQuit]

If your an adult who doesnt know this stuff by now get your shit together

[SheilaDuffy1950]

This is the best adult education I have ever imagined could help adults looking for classes regarding our interest in banking and purchasing a home.

[KrapZap]

Why am I here? I come to youtube to distract myself from homework, not learn what I'm actually supposed to learn :|

[InvisibleFriend77]

Very informative video! Very helpful lessons!

[DrDavidHowler]

KHAAAAAAAAAAAAAAAAAAAAAAAAAAAA­AN

[smnsohail]

/watch?v=LdqRuUXCruk

[acheeblessyou]

interest...ing

[Zander101084]

Sal, don't ever forget that you are the man!!!

[wolfecatte]

You didn't explain compound interest in the simplest way.

[hughie21]

This guy is awesome

[GREJFilmsLtd]

Note at 2:31 he writes 10/100 = $ 10% <==== he should not have written the "$" !!

but it's still a good video.

Also, pay attention to the DEFINITION of simple interest and compound interest.

[cmrnlza]

Hey I had the same anwers as your video but I lost you at 7.40 in the method ??

How did you get 100*(1.1)^2 ?? What is 1.1 ?

[wolfecatte]

@cmrnlza He had 110 + 10%(110), right? I lost him too, but then I remembered what undistributing meant.

The distributive property means that when you have something like 10(2 + 3). That property allows you to do (10)(2) + (10)(3). Both equations equal 50.

So if you undistribute 110, you would get 11 and 10, or (11)(10). Put the 10% in front, a.k.a. 0.1 since 10% = 0.1

10%(11)(10)

Let's take on the first part, 10%(11). That equals 0.11, right? And then you have (0.11)(10). That equals 1.1

[wolfecatte]

@cmrnlza (second part) According to Order of Operations (as you may know it, P.E.D.M.A.S.), you always do parentheses before anything else, and then exponents second. The exponent 2 on 1.1 is what you need to simplify first.

1.1^2, or (1.1)(1.1) is 1.21. And then (1.21)(100) is 121, which is the ammount you would owe in your second year of owning the money, being the principal $100 and the interest $21.

I hope this helped!~

[wolfecatte]

@cmrnlza basically, this is the thing:

P=principal

I=interest (in decimal, unless percentage sign is next to it)

A=ammount of years you borrow money for

P(1+I)^A

or

P(100 + I%/100)^A

[cmrnlza]

@wolfecatte

Hey Thanks for taking the time out to reply. I think I have to look at it a few more times before I get it.

But thanks anyways :) !

[wolfecatte]

@cmrnlza :) Mkay, glad to be of some help. :)

[4vlnstrings]

@cmrnlza Hey, I had the same confusion. Thanks for helping! Maybe you should teach. Do you?

[nathanraff]

seriously only 119K views. This is the most important lesson we need in the USA society

[Reewrat]

You just made my pre-calc teacher seem sooo much worse than she already is .

[alphamale227]

I didn't really care about school... until I met Sal Khan.

[VanyahaHeights]

You rock! Thanks a lot! 10 minutes and it nailed me!

[Jotto999]

Thanks very much!

[vickiormindyb]

I'd sure like to know what "a good Muslim" is. For lots of reasons, most of them personal, I'd be keenly interested in finding out what qualifies one to be "a good Muslim."

And I've never heard Sal say WHAT he is in terms of religion, so I don't see how anyone would know what he is.

[kermitcintronsucks]

is there such a thing as a good jew? I doubt it.

[vickiormindyb]

If you paid it back immediately, you wouldn't be like my brother.

I should have charged him interest on it. Maybe THEN he'd remember to give it back.

Never do business w/ family.

[vickiormindyb]

My friend, the economist, has heard your name. He's amazed and impressed that you gave up your former job title to do Khan Academy work.

He liked hearing your story.

If I didn't have him helping me, I never would have grasped what you're saying.

[vickiormindyb]

My economist friend doesn't like filing for bankruptcy either. He said it's better to make installment payments than to file for bankruptcy.

He was a banker. He's had a lot of different titles in the financial world. He did something with World Trade Exchanges, and he worked on Wall Street.

The last title he had, before the one he has now, was Hedge Funds Profiler. I think it's called that.

I have a really hard time w/ this subject. I took Bookkeeping 3 times before I passed the course w/ a C.

[groundzerobuild]

interest is haram or forbidden in Islam!

[abcman]

@groundzerobuild try telling all the banks in the middl-east that you ignorant moron

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[chinamofo]

i know this comment is a little lame but you sound like a such a nice guy! haha :)

[hwt2009]

i have a small inventory of bonds for sale.....do you have suggestions on how to find buyers?

[etramway]

Well done!

[Soldier957]

I'd like to hear Sal's comments on the financial info in the Zeitgeist films.....

[rumit99]

Anyone who plans on getting a loan should watch this. Very nice.

[ekmann99]

Great stuff, if you guys wanna read some books (free e-books) on the topic, check out:

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[wts1997]

very good!

[Animalchemy18]

Do you have a touchscreen or are you just that good writing and drawing with your mouse? I notice you are using ms paint. anywhoo great stuff mate, keep it up and thanks!

[TehRoflBot]

tnx this is going to help me on the AMC 8 test

[meganub10]

me too

[SuzumiyaHaruhi0]

AYA HIRANO

[SeekMeIn]

Excellent

[hamidmushtaq]

Interest = worst thing to happen to mankind! root of all evils!

[andresblazeit420]

yeah yeah, and the annunaki are coming in 2012 pfft

[vampySARAH]

thats why its forbbidn in the islamic financial systemm which turned out to be the least effected by the economic crises...

[Barryms0083]

does word pronounce "inter rest" or "intrist"?

[Paulorific]

Most people I speak to pronounce it with only two syllables, but I've only lived in North America.

[carbon544]

This reminds me of freshman year in business.Feels good to catch up on what you learned long ago.

[strapha3]

He got an MBA from H. Obviously it's not a real degree in the sense that getting an MBA in general is signaling theory with a huge dead weight loss attached to it.

Sal Khan was the fucking man before he went to H, which is why I stress the fact of his undergrad MIT making him what he is today.

[Sconz32]

Awesome.

[Studtoad86]

your a god

[lalsthefreak]

heyyyyy great viddd! i LAV it to teach me all these n3w things!

[miamimanni]

What is that your confused on?

Maybe I can help.

[hurricane223]

thanks man, your videos helped me alot..

[groundzerobuild]

@hurricane223 ~sal is a good Muslim!

[FerneJohn]

@hurricane223

"A lot." Two words.

[strapha3]

he obviously was an MIT undergrad

[JKB1989]

he reminds me of jeff goldbloom

[aplimanasa]

sal rulez!! ur the best... what are you a harvard professor?

[slamnxgirlxjulie]

your the best!!