How to Subtract By Adding

[@redkb]

You took an entire computer science lecture and turned it into a 3 min video! Nice!

[@yousorooo]

RedKB If your class takes a whole lecture to teach students about 2's complement, then you probably went to the wrong college.

[@are0planes]

Derek Leung Have you ever seen an MIT lecture? The spend the whole class explaining concepts just like this.

[@yousorooo]

Matthew Tayloe I've never watch any of their online lectures. The way I was taught is that we simply flip the bits and add one. This works because we don't have an infinite number line, instead a circular number line (mod) and flipping the bits just make it goes the other direction.

[@Minstorm34]

RedKB hey redkb, you watch minutephysics?

[@unvergebeneid]

Derek Leung RedKB If you can watch this video without ever having been introduced to the concept and then understand it deeply and fully _and_ still have a profound understanding of the concept two years later, you don't need college.

[@knollie199]

This is exactly what I need to know at 3 am.

[@matiaspetersen8779]

knollie thinking the exact same thing😂😂

[@ethanchou4906]

Play minecraft.

[@Take2TheStars]

Sad thing is it's exactly 3:00 as I'm typing this.

[@MALIWAL1000]

2:00 exact.

[@ReubertBarbosa]

1:24 hell yeah

[@coldspade1590]

20 seconds into the video and I would rather just subtract

[@vincentkhang5264]

hahhaha :D

[@gwen_gets_got]

Yep

[@margiekira1132]

VanillaChocolateJ aSame

[@Real_lifeRigby755]

Margie&Kira 113 tggggvydzydxmjcyk6to guff😀😍🐷😚💙💓😚💙🐽💓😚1234567880

[@vanessagarciatorres1117]

Honestly same

[@Burt1038]

"How to subtract by Adding" -proceeds to do a series of subtractions.

[@angeldude101]

Subtracting multi-digit numbers is hard. Subtracting single digit numbers is significantly easier, and you can get away with this since subtracting from the largest possible digit in a base can never borrow. In decimal, this is as easy as memorizing 0 9, 2 8, 3 7, 4 5. If you're a dumb computer and can't handle even that much, then you can do the binary version which is 0 1... and that's it.

[@Waddellaw]

I add by adding and subtract by subtracting. Never fails.

[@mr.champion7304]

but the question still remains, how do you subtract by adding?

[@fr0ntend]

@@mr.champion7304 better yet, how do you add by subtracting?

[@botigamer9011]

Any math problem will have dozens of methods to solve it

[@thenew3dworldfan]

It’s theoretically possible to divide by multiplykng provided the number we’re dividing by has a multiplicative inverse (or modular inverse) if modular arithmetic.

[@hayleydieckman8624]

Ready.... i know how to before the video starts.... *clears throat* 3+(-2)=1 Mind blown

[@tubzthepanda]

An adding machine cannot deal with negative numbers (which is why it is called an adding machine), so they must subtract by adding without using negatives.

[@Al-.-ex]

That's exactly the same as 3-2=1: same input, process and output. I really don't see why so many people don't understand this.

[@chlorobyte]

+ulagudie they COULD deal with negative numbers. Click 'read more' only if your brain is able to deal with computer math. You've been warned. Real signed values for a computer have the first bit off for negative, on for positive. We'll do examples with an 8 bit number, which goes from -128 to 127. We'll also do overflows/underflows, which are basically when you add one to 127 to get -128 and vice versa. Representation for +5: %1000 0101 And -5: %0111 1011 Well, that looks completely wrong. So let's flip all the bits and see what we get... %1000 0100 That is 4! I'll explain. If we had unsigned values (which are 0 to 255), +5 would be +133 and -5 would be +123. What is +123 represented as? %0111 1011 You can see it: you add 4 to get to 127, and 1 to get to 128 (or %1000 0000). So basically to convert an unsigned value to a signed value you subtract -128 (but the computer doesn't do this. the display engine does it) Let's try 5 - 2 as the example. Computer does this: %1000 0101 + %0111 1110 To add a number, if two 0's collide, nothing happens. If 1 and 0 collides (or vice versa), it becomes 1. But what if two 1's collide? The bit left to it gets increased by 1, and the bit itself turns into 0. So here's the steps that happen: %1000 0101 %1000 0111 %1000 1011 (Note that 1+1=10 thing) %1001 0011 (It just starts looping.) %1010 0011 %1100 0011 Then... You get the result, %0000 0011 Wait, where did that one bit go while adding it? It would be there if we were working with 9 bit values (or 16 bit values because they're easier to place it). Let's do the same math. We get: %0000 0001 0000 0011 That's overflowing. If the bit can't be added within the 8-bit range, then it's just ignored, and we get the lower 8 bits, which is the last two groups of numbers (I'm grouping them to 4 bits for more readability). And lastly, let's convert %0000 0011 to decimal. If you know how to do this, you'll get 3. And indeed, 5-2=3. Wow, this took me a TON to type, but I hope it's understandable.

[@chlorobyte]

i was about to edit the comment to correct a mistake but youtube doesn't goddamnit let me. anyway you need to flip the first bit after the calculation because that becomes negative something if you don't.

[@GameBanditPc]

I...wasnt...prepared...my head hurts

[@DanTheStripe]

Video length = 3:14 Pilluminati confirmed.

[@babatulani6361]

Wrong. It's 3.249 minutes long.

[@patu8010]

DanTheStripe Well, 3:13 but who's counting

[@DanTheStripe]

patu8010 KZbin always takes off a second :P In subboxes you'll see 3:14

[@zirconcrystal1869]

You mean Tauovertwoilluminati confirmed

[@cool2570]

π = 3.1415926

[@ihaveagun22]

how the hell did anyone just stumble across this rule what was he doing?

[@nelpski]

LSD. LSD is what he was doing.

[@Dakta96]

We use it in computers.

[@arrisfay]

+ClownsClaws thats not what he asked...

[@johnny45irish]

To compute means to calculate. Originally computers were people who specialises in computing large numbers mainly in their heads. To do this efficiently, short cuts would be helpful. This is where this, and many other short cuts were formed and used. Such knowledge is no longer really required for any practical use, apart from maybe to impress your friends at parties by calculating very large sums, although it can be useful in everyday life to know a few.

[@PopeLando]

Every time you make change from a dollar, you're creating complements. Every time you figured out a subtraction by thinking of what the change would be and then adding it, you have subtracted by adding the complement. At least this is something I've done for as long as I can remember, so I think this is how somebody "stumbled" across this rule.

[@YungPnut2404]

This is much more relevant if you know how computers do it. Lol

[@TheCreepyLuck]

I've been trying to explain how I subtract to my mom for years, this is gold for me

[@adamcetinkent]

I've only ever subtracted from my mum

[@jazzling]

@@adamcetinkent i ftreeaked your mom

[@woodfur00]

Um, but Henry, 2 + 2 still doesn't equal 1.

[@CaptainStino]

woodfur00 This depends in what space you are calculating.

[@libalchris]

woodfur00 It does in the finite field modulo 3

[@reasonnottheneed]

woodfur00 Of course it does! Also, 2^3 = 2

[@yoav116]

Apokalyps beat me to it xD

[@ihrbekommtmeinenrichtigennamen]

woodfur00 Eh. I'm sure you can fiddle it in by using a different base and a fitting number of digits.

[@fjoa123]

wow math is so flexible yet so restrictive. Like a rubber band choking a kitten.

[@pyromaniac000000]

Ya really, why?? Why a kitten?? Why not, say, a puppy?? Sorry I don't like dogs....I know I have issues...

[@javierlim4873]

PETA is now tracking your search history

[@fjoa123]

Javier Lim I love Kitties, just check my channel ):

[@VoidExileYT]

you have serious problems

[@joseantonio6637]

Damn, your comment is as dark as my soul.

[@FlyingKitty900]

Or just use a calculator

[@FlyingKitty900]

***** There's a calculator in your computer.

[@cedriccrystobalorleans675]

FlyingKitty Your profile picture fits your comment perfectly. :3

[@lobtyu]

FlyingKitty This is the cheapest way in terms of both circuit cost and circuit space to implement a circuit that can do binary subtraction in a computer. This method is really only relevant for electrical and computer engineers like myself, I just wish the author emphasized the point of how this is how computers subtract more greatly since it seems like the use of this method could be a bit hard to see.

[@ericcartmann]

FlyingKitty did you know your calculator does only approximations for lets say sin(1.52). most calculators are off by a few decimals. If you knew how the calculator works, you can just "mine" yourself a billion iterations of a Taylor series approximation to insure accuracy( you calculator does maybe 10-100 iterations depending on the speed/memory of the calculator) Even to do that approximation you need to know something about what minutephysics says. 64 bit machines can only have a number as large as 2^64 / 2 (negatives) or 2^64 (without negatives or unsigned). If we are dealing with unsigned 64 bit integers, what happens if you get a number like 2^64 + 1? Well this may sound counter intuitive, you just get 0, other interpreted languages well just cap at 2^64. with this in mind even your approximation algorithm will be off, of course you can correct easily using other algorithms. the point is recognizing that this is a thing.

[@Oshyrath]

FlyingKitty Your laptop doesn't have time to use a calculator when calculating addresses.

[@Kanglar]

After an entire semester of digital logic class, this 3 minute video finally got me to understand the actual reasoning behind 2s compliment :)

[@Macandcheese1818]

It's so simple why couldn't they just teach this to us

[@vaishanthjv2519]

Same! Finally understood why 2's complement works.

[@SlickNickP]

0:17 I don’t want to carry over, so let’s start by subtracting everything from nine, which is effectively the same thing but more steps

[@drmusa1003]

Not really, doing it that way is much easier cuz - by 9 dosent have carry

[@Dragonking3787]

So if I had 999,995 dollars, five more dollars and I'd end up with 000,000 dollars? Nuuuuu!

[@DaffyDaffyDaffy33322]

+Dragonking3787 It also means if you go 3 dollars negative in your bank account you'll have 999,997 :P

[@Dragonking3787]

+DaffyDaffyDaffy33322 Really? I'm rich!!!!

[@LillianWinterAnimations]

I have 0 dollars. All I need to do is give away 5 dollars, and I'll have 10^99 - 5 dollars!

[@jonathangamez952]

If your bank computer system doesn't work with enough digits, then yes. That's what happened with the Y2K bug.

[@oscarmendez1477]

Jonathan Gamez Really? Thanks! I did not knew that.

[@rinhato8453]

How does maths even work.

[@GivenFailure]

Rin Hato *sigh* this is why we need to rework math education.

[@zirconcrystal1869]

How does Meth even work

[@freeforallhi]

***** Yes! I always thought of it as such, but you were the first I've seen to put it so concisely!

[@GivenFailure]

One for All If you'd like to be even more concise: The examination of patterns in tautologies surrounding a rule set. That is math.

[@GivenFailure]

***** Math isn't scientific.

[@faciality]

but ur still subtracting.

[@johnkeefer8760]

OPULENT not in overflow on a computer

[@JamesR624]

Yep. Just clickbait. Most larger channels like this know most of their viewers aren’t very smart. The point of these channels isn’t education. It’s ad money. Pure and simple.

[@vertia2839]

Well the video’s still entertaining so... and besides if he really wanted that ad money he would've stretched it out to 10mons

[@vertia2839]

Mins*

[@abigailsokol3029]

​@@JamesR624 The point of the video was to show how machines (such as the adding machine shown, or more commonly, most computers) subtract numbers by adding rather than "real" subtraction. Most arithmetic logic units subtract numbers by first running a not operation on one number, then add the two numbers with the starting carry bit set.

[@Czesnek]

I have no idea what is going on in this video.

[@calvin3005]

+Czesnek Basically, he's talking about maths and shit.

[@Tremor244]

+calvin3005 I don't understand something....its probably maths and shit!

[@badmintonlover2720]

shit & shit

[@jackhooper2839]

So basically, for a - b = c, where b is a natural number (1,2,3,4...) with n digits, ((10^n - b) + a) -10^n = c The 10^n term cancels and you're left with: - b + a = c That makes sense doesn't it?

[@SpookyMontero]

+Jack Hooper thanks bro

[@AlexN5142]

I'm in my final year of getting my computer engineering degree, and have taken tons of courses on digital logic, designing circuitry that adds/subtracts, and learned lots of discrete math and modular arithmetic. And until now, it never clicked that two's complement IS modular arithmetic! You just opened up a whole new world of understanding for me. Thanks!

[@joshyoung1440]

Okay, so from that description, I'm pretty sure computer engineering is what I need to go back to school for. I dropped out of university after losing passion for my major (and getting addicted to drugs), but I never stopped learning, and I've been thinking about going back now that things are better, and so I was thinking about all the stuff I've been into since leaving school... chemistry was a huge part of it, but recently it's been taking apart electronics in an attempt to learn about computers in the most bare-metal, what-is-a-bit-and-how-do-you-command-throngs-of-them-to-do-your-bidding kind of way. Oh, and 3d printing on my fuckin $80 toddler's-first-3d-printer (lmao), so learning a tiny bit of 3d design, but I still wanna focus on learning the nitty gritty.

[@joshyoung1440]

Also, hope your computer career is taking off well :)

[@Dwagoner]

My brain is all over the floor

[@outlet6018]

This is the easiest video yet 10+ (-20)= -10 . Same as 10-20= -10

[@Jeffrey314159]

Outleteon Not quite the same for calcs

[@MusicalInquisit]

By calcs do you mean calculator or calculous?

[@rdococ]

AnimatorGeorge: Calculous?

[@shianeruu4359]

So it's overflow-ring

[@israellai]

Ah reminds me of the good old computer science lessons in high school. Add and ignore overflow.

[@charriu]

xXGoblinLord69Xx as a programmer: :(

[@666Tomato666]

xXGoblinLord69Xx So, how is the work at McDonalds?

[@BrennenSprimont92]

666Tomato666 Too be fair less than 1% of programmers are actually programming in a language low enough to use this information.

[@666Tomato666]

Brennen Sprimont I don't expect them to use this, I expect them to understand the general concepts and limitations even if you use languages like Java you still have to worry about integer overflow

[@daddyleon]

Israel Lai Yeah, but you´re still subtracting...

[@chelsie292]

424242 and 333333. I sense some Illuminati and explanation of life here

[@deadlydeath3245]

Chelsie And 666667 and 1090909

[@B870879]

Chelsie and illuminati sitting in a tree K I S S I N G

[@electromorphous]

0 vids and 80 subs on ur channel? How?

[@nigit7451]

Chelsie 666667 has 5 sixes and one seven which when added are 37, 37 is prime, 3 is prime, the illuminati has 3 sides, illuminati confirmed

[@kubatutak9452]

Now 777-666=111 Today i met number 6.900e111 69, 777, 666

[@Mudkip971]

*2+2=Fish*

[@JuliuSeizure]

7+7=triangle

[@Todaywalnut]

3+3=8

[@derekmartin5340]

u mean 2+2=The Quadratic Forumula

[@adiramrakhani]

1+ 1 = window

[@jellybeanjustin82]

Mudkip971 no it equals 5 (Radiohead joke, search 2+2=5)

[@andretsang7337]

2's complement, eh? *YOU LOOK VERY NICE* Am I doing this right?

[@VonUndZuCaesar]

+1

[@lalalalalalalalal567]

You should say "you look 2 nice"

[@Artorus]

I liked this comment, then unliked it so the Like Counter could stay at 69.

[@robertpeacock2015]

+Amos Tan I liked it anyway

[@lalalalalalalalal567]

Robert Peacock Nooooooo

[@ScienceAsylum]

I remember learning this as follows: Subtract *all* the digits from 9 and then add the first digit of the result to the last digit of the result: 1425 - 0923 ---> 1425 + 9076 = 10501 ---> 502 ...but I suppose it's essentially the same thing. I had no idea Hank's machine did things this way though. Cool.

[@Misitan]

hello verified man who absolutely destroyed me when I tried to farm likes in your comments

[@jazzling]

i love you

[@chinomsookafor4564]

How to subtract by adding: use negatives.

[@TealJosh]

Can no do for computers

[@Fillster]

But then you still would indirectly be subtracting.

[@sporkafife]

How do you subtract by adding? Okay, here we go... first... DO A LOT OF SUBTRACTING :D But it's only single digit subtracting, so it's nicer :P

[@Dobendanx]

sporkafife You can break down the "lot of substracting" to adding, too. In binary it's even easier, you just flip every bit and add a 1, and you are done

[@yousorooo]

sporkafife In binary the only thing you do is just flipping the bits, which can be done in parallel by slapping in XORs, which is extremely efficient.

[@neeneko]

sporkafife it is a lot cleaner in base 2.

[@eideticex]

Derek Leung This is actually the same thing as binary. Decimal inversion is 9 - X, where 9 is the largest single digit value. Binary inversion is 1 - X, where 1 is the largest single digit value. Also the number he threw away at the end should be familiar too for 2s-compliment familiar folk, it's the sign digit.

[@rangedfighter]

sporkafife you can do the single digit subtraction in your head, because every digit will be turned to the same digit always, then just add +1 to it at the end 1 will always be inverted to 8 2 to 7 3 to 6 4 to 5 and vice versa

[@RaiOkami]

This is basically tens complement, right?

[@TheSinfulFreak]

RaiOkami exactly!

[@Zarggg]

RaiOkami Yes!

[@moocats]

Pretty much

[@AlqGo]

complement of 10 raised to the power of some n, where n is the number of digits of the number to be subtracted

[@themegadrivekid7721]

*walks to computer* Hey computer? "hello fellow nerd" I heard that you subtract by adding. "that is correct" So how do you know how to subtract 9 from each digit. Windows has encountered an error, and needs to shut down.

[@quinn7894]

"'i' simply xor the main number with all ones and add one"

[@De_Swink]

@@quinn7894 This is not true. Two's compliment works by inverting all bits and adding 1. If you XOR all bits with 1 you get a gibberish number that has no mathematical meaning for calculations.

[@fullfungo]

@@De_Swink They didn't say XOR with one, they said XOR with ALL ones, which would be a number consisting of only ones.

[@jetison333]

Yall xoring with a one is the exact same as inverting the bits. Go look up the truth take if you have too.

[@yuvalmaharshak5566]

don't know how computer do it but he can just keep adding ones and check how many one's have been added until nine

[@EnderCrypt]

yeah, but you still have to substract, lel

[@Jayoshi32]

+EnderCrypt you use the difference from nine or ten, not subtract. There's a fine difference between the two.

[@EnderCrypt]

Jayoshi diffrence uses subtraction, basic subtraction, subtraction nontheless

[@Jayoshi32]

EnderCrypt Actually, it doesn't have to. You can use the smaller number, and count how many times you add one until you reach the bigger number. For example: 4 < 9 4+1 = 5 (1) 5+1 = 6 (2) 6+1 = 7 (3) 7+1 = 8 (4) 8+1 = 9 (5) And four plus five is nine. So, using the 1492-1066 example: difference between 1 & 9: 1+1 = 2 (1) ... 8+1 = 9 (8) *8000* difference between 0 & 9: 0+1 = 1 (1) ... 8+1 = 9 (9) *8900* difference between 6 & 9: (laughter is allowed) 6+1 = 7 (1) 7+1 = 8 (2) 8+1 = 9 (3) *8930* difference between 6 & 10: 6+1 = 7 (1) ... 9+1 = 10 (4) *8934* 8934+1492 = *10426* without the 10000: *426* Never subtracting a single digit.

[@EnderCrypt]

Jayoshi *subtraction* "Mathematics. the operation or process of finding the difference between two numbers or quantities" so yeah, thats still subtraction

[@Jayoshi32]

EnderCrypt but you use addition methods to subtract. In computers, subtraction _must_ be composed of addition. It _cannot_ use subtraction directly, so your claim is incorrect that this method uses subtraction without adding. E: never mind, I see where you were coming from. The thing is that it doesn't take away a quantity, which is another definition for subtraction. (more specifically, to subtract)

[@sterlingarcher3857]

so to subtract by adding you need to subtract? okaaaaayyy

[@larsvanpeer6311]

That's exactly what my brain is going through now.

[@Spark31Gaming]

Finally! A video by you with something I already knew about! I've been subtracting by the two's complement for ages now.

[@amier2k1]

dont fuck me up like this

[@themaldi1]

Your avatar makes this comment even funnier.

[@mathiaskjeldgaardpetersen5926]

+larlol2001 Yep there is a fake Minte Physics account made to scam you. but it's easy to spot the fake account, it has 0 subs and adversatives stuff like: FREE give-aways of 100 new Iphones just click this suspicious link. Henry wouldn't add links in the comments but in the video info

[@amier2k1]

Mathias Petersen i know ialways report them

[@zachogilman7397]

larlol2001 Well, I don't think it's fake because its run by a REAL person, Henry! Plus that's the greatest subtraction method I've ran into! Try to solve 185-92 in 15 seconds just rounding and then give another 15 for subtracting by adding. Well... Okay, okay! The method is take 9 minus the digits to the left of the ones place and 10 minus the final digit. You then add your new number to your larger number. and then you ignore the first digit, resulting in your answer! 185-92= 93 185+08=193, or 93

[@zachogilman7397]

Zacho Gilman Yes it is a cute puppy!!!!!!!!!! ;) ☺☺☺☺☺☺☺😁😁😀😀😀😁😁😁😁

[@Liamv4696]

This is basically me in my programming class at uni. Just like, lolwut

[@gustythebest]

Liamv4696 I'm in my second year of Comp Sci and they have never spoken about this... Well maybe they have but chances are I wasn't there.

[@Liamv4696]

Gusty Abra Im doing a mechanical engineering degree, yet i have to do two electrical systems units and a programming unit. Still waiting to do some physics...

[@TheCh0senOne]

Liamv4696 Seems only logical, right? Computers can only perform 3 basic functions: adding, comparing and transfer of data. When I watched this, programming was the first thing that came to my mind. Reminds me a bit of "Russian Multiplication".

[@BrennenSprimont92]

Gusty Abra My school covered it at the 3000 level in a class rightfully abbreviated as "CAOS" (Computer Architecture and Operating Systems). Not a good time.

[@lobtyu]

Brennen Sprimont My school has all electrical and computer engineers and computer science majors take this in their first year in a 100 level class. And then we used this concept to build a microprocessor that could subtract, among other functions lol Literally one of the hardest classes I've taken.

[@Varsei]

who else just blank out in the middle of the video?

[@ahuttee]

Not me

[@harvirdhindsa3244]

Most of the commentators here have no idea what he was stressing in this video. Although this may not be practical for you on a daily basis, it is how machines work. And machines are essentially the future so it is vital to know how they work.

[@SonicMusicVape]

He should've added, "How computers do it" in the title

[@markoftheland3115]

how to subtract by adding? SUBTRACTING every single one of the numbers from 9 and then do the adding process. okay then...

[@pyritenightmare]

This was 2 years ago, I know, but using addition to make the number equal to 9 (for example, with 6, you'd add 3), then use the number you added. (Same thing with the final digit but with 10.) No subtraction needed!

[@thomasslone1964]

Marcos Landi this process still requires a form of subtracting so how do I make a binary

[@waltblackadar4690]

It's still subtraction, Thumbs down.

[@FriendofWigner]

I have been using this principal for off and on for almost 15 years now, and this is the first time it actually made sense to me on an intuitive level. You did in three minutes what multiple professors, books, and videos couldn't. You, sir, are a rock star.

[@SonicRooncoPrime]

Amazing how quickly the views roll in. Great work MinutePhysics!

[@nataliesnooks]

SonicRooncoPrime I know right.

[@MontagoDK]

i discovered this myself in 3rd grade: Division by 5 is the same as multiplying by 2 and dividing by 10 eg: 45 : 5 = 90 / 10 = 9 47 : 5 = 94 / 10 = 9,4 etc...

[@palmomki]

***** Well... you were a smart kid. But... how does this relate to the mechanism proposed in the video? XD

[@MontagoDK]

palmomki not much, other than being a calculation trick.

[@Skiddla]

***** careful young watson, you also need to divide your reminder by 2 :o)

[@palmomki]

***** remainder? he's not using exclusively integers, he won't ever get any remainder

[@MontagoDK]

***** what remainder ? try punching the numbers into a calculator

[@bailey125]

You are still subtracting but you are just doing it individually to each digit. Unless you predetermine the numbers: 1 = 8 or if it is the last digit: 1 = 9 2 = 7 2 = 8 3 = 6 3 = 7 4 = 5 4 = 6 5 = 4 5 = 5 6 = 3 6 = 4 7 = 2 7 = 3 8 = 1 8 = 2 9 = 0 9 = 1 0 = 9 0 = 10

[@nuklearboysymbiote]

Exactly. Doing it by each digit is what makes it diferent than the conventional method.

[@Jeffrey314159]

I thought he was using the 9's Compliment to subtract, like those cheap electromechanical adding machines(from the 1960's) used to subtract. Those simple machines couldn't calculate with negative intergers for their motorizing components rotated in one direction.

[@connorhorman]

If you do it in binary, it's free to do so.

[@michaelhanford8139]

predetermining the numbers still requires subtraction tho. Tho that's what the makers of the adding machines must have done. Lol back to back 'thoughs'! 😄

[@Just10tb]

This is more complicated than just subtracting it.

[@Roxor128]

Justin Baldwin Not really. If anything the borrowing mechanism of conventional subtraction is more complicated than "invert the digits and add one".

[@Nemoticon]

***** No

[@Roxor128]

Rogue Qall "No."? Is that all? No explanation why you disagree?

[@Nemoticon]

***** Strait up subtraction isn't that hard to do at all. I'm pretty poor at maths, but addition and subtraction isn't something I need a mechanism for. Be it mentally or written on paper.

[@shadfurman]

Rogue Qall I think you're ignoring your experience with subtraction. Its not about it needing a "mechanism". I imagine if this were the way you were taught to subtract as a child it might be easier. The point of it is that its a different way that can be better is SOME cases. It seems to me in a brain calculation case, training and experience being equal, these would be roughly equal.

[@anasofxa9804]

How to subtract by adding: OK FIRST U GOTTA SUBTRACT EACH DIGIT FROM 9 AND THEN- Yeah that was really eye-opening minute physics thanks for showing me how to subtract by adding, especially the part where you told me to do subtraction

[@neelamverma8167]

This video was posted one month late than when it should have been...

[@tgseidel]

looking for channnels like vsauce and minutephysics? any suggestions? :)

[@RockSmacker]

Tobias Seidel Check out Veritasium; amazing work

[@enricomercadante5171]

Tobias Seidel Veritasium!

[@enricomercadante5171]

Tobias Seidel Veritasium!

[@BhupinderSinghSaini1]

Tobias Seidel Smarter Every Day, Veritasium, Scishow, ViHart, Asapscience

[@michal3003]

Tobias Seidel veritasium

[@messianicrogue]

whooosh.... straight over my head.

[@saftaisland3427]

OMG i wish i saw this during my year 12 software classes. The way my teacher explained it made it go straight over my head but this is so easy to understand.

[@Tocaraca]

2+-1

[@ishrak1813]

1

[@Tocaraca]

Ishrak Khan lol

[@iqbaltrojan]

+Ishrak Khan* 0** *D0 i reconize that name? **0 = 1^ ^as l0ng as y0u d0nt l00k t0 far 000

[@hagalathekido]

its 1 m8

[@Al-.-ex]

This is exactly the same as 2-1, just written differently: same input, processes and output. All you did was add a '+'. Btw it's 2+(-1).

[@halithegreat3240]

I know how to subtract by adding! 8+-1=7. MAGIC

[@a.f.nik.4210]

u 2's complement?

[@halithegreat3240]

Wafflez the Great Its called joking you moronic kindergartner.

[@petrkdn8224]

you can.. you add a negative number 2+ (still positive number) -2(negative number..)=0 so that means you add negative number

[@adiramrakhani]

yes you can

[@daredevil3744]

Yep...

[@XY_Dude]

I learned this sometime ago when I was repairing mainframe computers. Those computers did everything by adding and bit shifts. Cool.

[@CatalystEXE]

commoncore.mpg

[@VentMagic102]

amen.

[@Oshyrath]

+CatalystEXE Not common core. Computer architecture. As a guy who's majoring in CE, this video makes perfect sense.

[@VentMagic102]

Oshyrath thanks for playing

[@dionaeamuscipula6649]

+Oshyrath ( ° □ °)-°•¤•°○☆ SHIPPIDY DIPPIDY DENCE! I FORCE YOU! TO NOT MAKE SENSE

[@CatherineLu]

That was pretty cool.

[@louiejohncastillo9822]

you almost touched the p-adic numbers.

[@MegaCalin88]

Anyone else feel dumb after this?

[@chiggawaffle04]

Nope

[@diondredunigan2583]

+Calin H No

[@adamross9626]

meh,nope

[@girlrants1334]

Yes and I am Asian 😮

[@wintersolstice3573]

+Calin H Already knew this since I studied logic circuits and switching theory :) They do it in EXCESS 3 (or in short terms to add a +3 to any given number) to correct the computing error that +0 is greater than -0

[@mazowskii3342]

2+(-1)=1 done.

[@doctorblaze5497]

that's it the same thing as 2-1 as adding a negative is subtraction, subtraction is the addition of negative numbers but just removing the addition sign and leaving the negative sign means the same thing. Adding negative numbers is just subtraction but usually used for reorganizing an equation so if you wanted to reorganize 2-1 you would go -1+2 which is the same thing.

[@XavierAliatos]

I wasn't sure where you were going with this until you mentioned the adding machine, then my comp sci background kicked in. Clever way to frame the idea!

[@adityakhanna113]

Thanks Henry, I just recently studied the two's complement ..,. I didn't know its use... Until now... These videos are as great as your physics' ones... P.S. 424242 .. Got that reference.. We all are obsessed with 42 ,aren't we XD? Plus it's 101010 in binary... Alternating digits everywhere!!

[@JNCressey]

Aditya Khanna Actually, 424242 Dec = 1100111100100110010 Bin. 101010 Bin = 82 Dec.

[@adityakhanna113]

I was talking about... 42 Dec = 101010 Bin Like 424242 has alternating decimal digits . 42 ( 101010) has alternating binary digits

[@JNCressey]

Aditya Khanna Sorry, when I did Bin→Dec on 101010 I accidentally did _2+2^3+2^6_ and got 82 instead.

[@adityakhanna113]

JNCressey I understand it happens, man! :) Chillax!

[@claraisweird6395]

Forty-twooo... ;D

[@q-tek8349]

"Subtract by adding" Process: *subtract* 9 from each digit and 10 from the last

[@dotted_stains2792]

👁️👄👁️

[@roy04]

Always took it as a given and never understood much how, but two's complement makes so much more sense now.

[@Shangori]

I love math! And computers! I love this video!

[@Adokebab]

Let me guess Your asian :)

[@seppeldiseppsepp]

Shangori its not just love, its love²

[@Shangori]

I cant find a name Not at all. I'm dutch. But, I work with AI systems and I enjoy math more than language. More predictable

[@pablez94]

I cant find a name and you're racist! :D

[@MagnusSkiptonLLC]

Shangori I hate computers. And my day-to-day job is programming...

[@DaniJaxJarcor]

Lenght of the video: 3:14 Icy wat u did there.

[@idkwhatamidoing8159]

2:37 you still have to subtract when you do 9-8 or something like that

[@Owen_loves_Butters]

The nice thing about binary is subtracting from 1 just inverts the digit

[@ryPish]

Cool Numberphile video, too bad it's on the wrong channel D:

[@ericcartmann]

georgyorgy2 dont be a fucken jew.

[@georgyorgy2]

***** Ok, Kenny.

[@user-ez5vq9fd2t]

Ry P shots fired

[@gandhi5222]

Cat the Turtle

[@OscarCookeAbbott]

Great for subtracting by adding... Except that it requires you to subtract numbers from 9 and 10...

[@k2saf]

Oscar Cooke-Abbott or maybe, you could do add (for example) 5 +9 = 14 and just take the 4 ( 9-5 = 4 ).

[@OscarCookeAbbott]

k2saf true enough

[@unaliveeveryonenow]

Oscar Cooke-Abbott or make a lookup table with 10 rows

[@SerenityReceiver]

k2saf nope...use a different number to check your hypothesis.

[@BlurryButInHD]

k2saf doesnt work with 7-6

[@NonTwinBrothers]

I remember watching this in middle school. I remembered it 9 years later while writing an arbitrary-length integer class :D

[@user-kd4mi8xb7p]

What if I don't know addition?

[@magnus.magnusson]

Kim Jong-Un then use rocks.

[@Gruncival]

Kim Jong-Un Addition is just "faster counting", so you just have to remember how to count by numbers greater than 1, my Great Leader.

[@mrhappy192]

Subtract 9 from every digit and subtract the numbers. You should get the correct result except the first digit.

[@emileighmatthews4955]

I'm just going to subtract...

[@theknowitall2763]

This is the method I use for subtracting from powers of 10, but I never knew we could do it for any number. The more you know.

[@mcgelloe]

Nobody in the comments section understood the video...

[@kyletzzff125]

That's just your opinion, I understood it perfectly.

[@niranodoneh782]

Fix: MOST people in the comments section didn't understand the video.

[@omgitsjezus]

I understand it others don't xd

[@HandledToaster2]

I, an intellectual, understood the video.

[@MrJason005]

8+(-6)= 2 My maths teacher has turned our way of thinking upside down, she wants us to see subtraction as adding.

[@pharos640]

In the middle of the video I remembered that in computers if you want to subtract A - B you just flip the bits of B and add them together. Also cool explanation

[@catchthesehands2936]

Yep I saw this and immediately resized it was 2's compliment for base 10 :p

[@Sal-zi4tu]

SPOILER: the concepts explained matter to a computer scientist, not 8 years old below.

[@jacobrickayzen2744]

i got introduced to this video, and this entire channel, by a friend and i was fascinated by this video so i learnt and practiced and eventually mastered this technique. i soon after had a maths test but there was one slight problem... i somehow forgot how to column method for subtraction. i was young at the time and i remembered that is learnt how to subtract by adding so i did this method, got the answer correct and confused the hell out of my teachers because is showed my working out. :)

[@jacobrickayzen2744]

i* not is

[@MiRaje8086]

you still have to subtract lmao

[@ads1021]

Yes, but because he presented an imperfect alternate to the actual method.

[@jevotepour]

so you have to make five subtractions plus one addition for the same resulte as a basic subtaction. how useful...

[@fieldinterference]

Tovi Pavatam It seems "minute physics" uses the opposite mentality from Occam's razor ...

[@MidiMaze178]

this video actually put me to sleep. it wasn't boring I was just really tired and I fell asleep.

[@overpowered5919]

I think I prefer using my calculator:)

[@toxicore1190]

this actually is used in computers

[@melvillefletcher4332]

Toxi Core Did you even watch the video?

[@toxicore1190]

Melville Fletcher wrote this while watching the video so yeah ..

[@yousorooo]

Toxi Core Should've watched the whole video before commenting...

[@toxicore1190]

Derek Leung yes captain obvious lol

[@johnny45irish]

You can also multiply the number you want to take away by -1, which makes it a negative number, which when added to the original number, does the opposite and subtracts.

[@adriancarpio7536]

999 gajillion 999 bajillion 999 XD

[@VincentGuillotine]

lmao it's easier to just use regular subtraction

[@Zarggg]

VincentGuillotine You completely missed the purpose of the video.

[@VincentGuillotine]

Zarggg ok well you can enjoy the video's purpose while I do subtraction the fast and easy way

[@jasondoe2596]

VincentGuillotine The "fast and easy way" is using a computer. Guess what, computers do exactly what is shown in the video.

[@VincentGuillotine]

Jason Doe haha as if the fast and easy way is to use a calculator not a computer smh

[@jasondoe2596]

VincentGuillotine What's the difference? Trolls gonna troll, I guess :)

[@blank3211]

I like how he tells me I'm going to subtract by adding and not have to subtract but the first step is to subtract the digits

[@kekships]

Why do 1st grade teachers never teach this?

[@ontariolacus]

Because it's just easier to use calculator in real life?

[@PigsBeFlying]

+ontariolacus but you won't have a calculator with you everywhere you go, phones don't exist, you have to take this math class

[@ontariolacus]

Not Important That's not a reasonable argument. It's better to teach children survival skills. Finding in a place where you don't have access to a calculator and at the same time in dire need of speedy calculation is much less probable than say making fire. Don't get me wrong, I like math, but basic hand calculations that children are taught are more than enough.

[@PigsBeFlying]

ontariolacus sarcasm*

[@ontariolacus]

Not Important Poe's law makes sarcasm pretty useless for random comments.

[@SteveGottaGoFast]

Cool Cool, but what does that have to do with physics?

[@SteveGottaGoFast]

***** kk

[@aru05001]

I did this as a kid, my teachers put the kaibach on that one...thank you for reminding me how it works.

[@kimmyawesomeness4184]

i thoguht he was gonna be like"YA'LL CAN ADD A NEGATIVE AND BAM! IT'S LIKE SUBTRACTING!: I was wrong....

[@sumobear1777]

how high is gazillion? I know million billion trillion quadrillion quintillion septillion sextillion octillion nonillion decillion undecillion - all the way to centillion and its no where in there.

[@meowtasia02]

+Pat P gazillion is a made up word

[@TrumanHill]

+Pat P lol cause gazillion isnt a number just an expression for a large digit

[@SSDARKPIT]

Too many illions.

[@nhaugen5975]

+Pat P But sextillion comes before septillion.

[@PotatoMC1]

Million billion trillion quadrillion quintillion sextillion septillion octillion nonillion*

[@balf1111117373]

I do this subconsciously, I see a mathematical question and instantly the answer pops in my head without working anything out. I then work out the answer and it's correct

[@phillytothemax]

Peanut butter.

[@CatholicismRules]

Does this mean that when I subscribe to you I'll really be taking a subscription away? And that when someone unsubscribes to you they really subscribe?? Does this mean that I should dislike the video and write a negative comment, meaning it's positive, promoting your channel!? So if it's been 1 hour since I last ate then it's really been 1 hour until I will eat again?? But wait no! Because eating again implies I've already eaten! And since (this time) - (1 hour) really equals (this time) + (1 hour) does this mean I've never eaten?? I've never had Chickfila!! Dx I don't like this, it's too confusing. But if it's too confusing that means it makes perfect sense. I don't get it. I made my house a mess, which was making it clean, which made Squidward clean my yard, but that really means he's messing it up. But the opposite of clean is filth, which means filth is clean, that means Squidward is really making my yard a wreck, but I normally wreck my own yard which means, Squidward is being the opposite of Squidward which means he's SpongeBob! A-ha! I understand everything perfectly now! I'm just kidding of course, I understand how this works lol.

[@vsrirampriya6972]

Sensei Jack is likes thats comments becauses is likes this facts thats yous tooks yours times tos writes suchs as uselesss comments

[@chickennugger6029]

Sensei Jack just unsubscribe...

[@isaacw3212]

Sensei Jack I was getting a little worried for you until I read the last sentence lol

[@Yui714]

Or simply find the difference between the two numbers by adding on to the smallest value until it reaches the higher value. 1324 - 960 = 40 + 324

[@DeadUnicornClub]

If you want to subtract without subtracting your first step is to subtract...??? This trick is probably really good for machines, but for me personally it seems like there are more steps involved than regular subtracting. A cool trick, but not something I'll use.

[@Evilovedoctor]

dude you can just take 1492 - 1066 and get the answer

[@Evilovedoctor]

I refuse to believe that you people did not know that

[@lobtyu]

Evi You completely missed the point of this. This is how anything using circuits subtract. This is by far the cheapest method in terms of both circuit space and material cost to implement a subtractor circuit.

[@izvarzone]

That's what I did.

[@loiclejeune2877]

i'm trying to make a caculator in minecraft right now and this is going to help a ton

[@teyfc2461]

but you are not just adding. 9-1, 9-3, 9-6 and so on....

[@MLGRuthless]

TeyFC I know right

[@hprobertos]

He told that the machine just rotates the numbers, its not substracting anything

[@chickennugger6029]

TeyFC the guy just threw up a bunch of numbers onto a screen, swapped around some number sums and bob's your uncle, you made a video that doesnt make sense.

[@teyfc2461]

I made a video that doesnt make sense?

[@yehoshuas.6917]

+TeyFC i get what ur saying, but this is supposed to make it easier, not necessarily just never subtract. However this subtracting never requires borrowing since it is always 9- a one digit number which is between 0-9, 9 is always greater than or equal to that number, borrowing is never required. I still don't like this method since it always requires an additional step for each new digit, while doing subtraction may take either one or two steps, and addition takes at least one,so the normal way takes an average of 1.5 steps/digit, and this new way requires 2.5 steps/digit.

[@TheOfficialSassafras]

I didnt understand anything

[@OnlyFabz]

TheOfficialSassafras I actually understood it all perfectly and english isnt even my native language (kinda hard to understand other videos sometimes because they speed up video when talking), Its well explained why would you get lost?

[@fabiosoares4450]

TheOfficialSassafras Watch it again until you get it.

[@OnlyFabz]

i know exactly what he meant... he meant he didnt understand the process of the substaction, i just told him that it was perfectly explained and there shouldnt be any reason to get lost, thanks for your comment but it was totally irrelevant -_-

[@TheOiseau]

This is "ten's complement" addition, the equivalent of "two's complement" in computers.

[@Burn1ngR4g3]

777-222 9-2 9-2 10-2 778+777=1555 777-222=555 totally more easy

[@Astro2024]

+Burn1ngR4g3 777-222=777-200-20-2=577-22=555 easier