How Predictable Are You? Three Digit Magic Trick

[@yaiirable]

We don't need to use a brute force solution here. Given the fact we know that a > c and b = b, The final step will always look like: (a- c - 1) + 9 + (10 + c - a) = 18 We know that the final term will need to borrow a 1 that will be carried over all the way from the hundereds columns. a's and c's cancel out.

[@staffehn]

Yes! Another one with the same mindset ^^ (compare my comment up there)

[@yaiirable]

ABC - CBA imagine you are doing the subtraction. You start with C - A, but because A is bigger than C you need to carry the 1 from the B column. This makes the first term equal to (10 +C) - A. Then you do the same with the B column and then you are left with the final step I outlined above. Then cancel out the variables when adding all together to get (a-c-1) + (10+B-1-B)+(10+c+a). Hope that's more clear

[@Tehom1]

0:34 Let's follow this trick using algebra: Pick a 3-digit number: I pick x*100 + y*10 + z, and I'll write it as "xyz" Reverse the digits: zyx Subtract the smaller number from the larger number: xyz - zyx = (x-z) 0 (z-x) And I need to fix it up as a decimal, using the fact that xyz is larger so x > z: (x-z-1) 9 (10+z-x) Add up the digits of the result: x - z - 1 + 9 + 10 + z - x = 18

[@pupskanonel.jackson6722]

What

[@Tehom1]

@@pupskanonel.jackson6722 Showing that it works for all 3 digit numbers.

[@alloosworld1235]

Uncle, my grandpa was maths teacher in a school so he teached me this awesome trick but now he left last year but I forgot this trick so then I saw your video so thankyou for explaining this much easily . Anyway thanks . I was crying cause I remembered my grandpa..Tnks a lot.🙂🙂😄😪😔🤧🙁😁😁😁

[@zimeirbarrett5577]

The number has to be 18 me who used a negative number ;-;

[@fredrikenetorp1173]

Didn't work. I choose 0x4BA 0x4BA --> 0xAB4 --> 0x5FA --> 0x1E = 30 which is not equal to 18 nor 0x18.

[@purpleice2343]

0x4BA is 1210 in decimal :) Not a 3 digit number. In mathematics we never use anything but decimal, nice try though.

[@staffehn]

wrong.. where would you talk about different number systems if NOT in mathematics?

[@purpleice2343]

Some people might prefer using base-12 system. But we use only base-10, other bases are used only because we have hardware that can have only two states, hence why binary is even needed at all, other bases are just to make it easier for whoever is working with that, nothing to do with math at all. It's just number systems. You're just trying to abuse differences in number systems and "prove" that it doesn't always work. It's like I told you to fucking ask something from someone who understand only english and you brought your fucking ancient egyptian hieroglyphs and asked them to read that question. It's fucking useless, inconvenient, and nobody fucking understands it without having to convert that information into something everyone understands. We don't use different number systems in maths, hexadecimal is convenient only because you need 2 characters to represent 3 digit number in decimal, other than that, it's confusing and you can't really tell. How many digits 64 has? Trick question, 3, because it's hexadecimal representation of it, actual number is 100 : ^) Oh wait, anyone here wants to use 64 to write what we know as 100?

[@staffehn]

Let’s stay on the topic of maths and not the topic of everyday-number-usage. What matters is that the statement of the trick depends on the base chosen for representing the numbers and that this should probably better be explicitly mentioned when posing the problem. Even more interesting is the fact that, actually, the reason why the trick works has nothing to do with the choice of the number 10 as a base-that is-choose any base, and you’ll get 2b-2 or 2(b-1) as the result. For base 10, that’s 18 ..for base 16 it’s 30 ^^

[@staffehn]

Also "100" is the octal representation of 64.. its hexadecimal one is "40". Hexadecimal "100" is 256 ;-) And it’s impossible for a (whole) hex number to be longer than the same decimal number. The length of a natural number x in base b is always floor(log_b(x))+1. And that function is antitone in its parameter b.

[@AndreasWoykepianistandcomposer]

Just to add: The result of each one digit number multiplied by 99 will be a three digit number with a 9 in the middle. The other two digits are supposed to add up to 9 because the checksum of each number divisible by 9 is also divisible by 9. So the result will always be 18. Like it!

[@staffehn]

oh.. I like this approach ^^

[@donnovanash2334]

Bro doesn’t like binary, thinks it doesn’t exist

[@donnovanash2334]

0 x 99 = 0 1 x 99 = 99

[@badrunna-im]

Letting the number be ABC, from ABC-CBA we see that B cancels out. Starting with a base case where A=2 and C=1, the difference will equal 99. Adding n to A will add 100n to the difference but also subtract n from it. The result can only be shifted by (100-1)n, or 99n. 99 from the base case +- 99n is also a multiple of 99. Since 99=100-1, a multiple of 99 can be expressed as 99+(100-1)n. This shows that, between 3-digit multiples of 99, any digit's addition in the hundreds place is canceled out by the subtraction in the ones place. Without carrying over, i.e. when the last digit's 0 (990), the tens digit stays constant. Thus the sum of the digits is constant and 'guessable' within the constraints given in the question.

[@ProProboscis]

At this point you may need to create a kids' version of your channel.

[@purpleice2343]

It is already full of braindead kids who can't follow simple instructions, don't worry.

[@user-nu6ge7px7s]

776-677 = 99 9+9 = 18 422-224 = 198 1+9+8 = 18 is break the rule but still get 18

[@BlinkLed]

I don't know why these simpler videos always get so many dislikes. I appreciate the mix of content on the channel.

[@ihordrahushchak5439]

numbers=[] for x in range(100,1000): if len(list(str(x)))==len(set(list(str(x)))): reversed_num=int(str(x)[::-1]) if reversed_num>x: subtracted=reversed_num-x else: subtracted=x-reversed_num added=0 for i in list(str(subtracted)): added+=int(i) numbers.append(added) print(set(numbers)) Output: {18}

[@okaro6595]

The first number of the result is a-c-1, the second 9 and the last 10+c-a. Add these and the variables cancel each other and you get -1+9+10 = 18.

[@Packerfan130]

Paused the video. Let 100a + 10b + c be your orginal number where 0

[@michaelempeigne3519]

Make more of these math videos please. Mindyourdecisions

[@sebastiansimon7557]

No, please don’t… those are trivially proven; far too easy and thus boring.

[@TheOriginalFayari]

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[@antforeargar3523]

Other solution: abc - cba ------- a0c - c0a ------- There will be a 9 in the middle because a>c The Numbers will now be: a-c-1 (-1 because you need to borrow so that you can borrow from the middle number) , 10-1 , 10-(a-c) (the 10 is from the middle number, and c-a = -(a-c) (not actually necessary, but That's how I solved it)) Now we add all of the numbers. a-c-1 + 9 + 10-(a-c) = a-c-1 +9 + 10+c-a = a-a+c-c+10+9-1= 18 Answer will always be = 18 (This Was all written on a mobile device)

[@user-nu6ge7px7s]

If I break the some rule It can also work some same digit with first digit and second digit Or same in second digit and last digit It only didnt work is first digit and last digit is same number 644-466 = 198 1+9+8 = 18 But if 464 - 464 = 0 You can change "with 3 different digit" to "with first digit and last digit is different number"

[@elchuchulo]

If you were to use hexadecimal instead of decimal, would it still work?

[@purpleice2343]

In math we don't use anything but decimal.

[@sebastiansimon7557]

For any base b, you’ll get 2b - 2.

[@sebastiansimon7557]

Shadow Lurker - Congratulations on winning the prize for the Least Intelligent Comment of all Time!

[@Sir.BlackHole]

mh... from 3,14 to 3,41 ok now i have 0,27 0 + 2 + 7 = 9

[@silverseacow]

This is what I call mathemagic

[@seersam]

|100a+10b+c-100c-10b-a| = |99a-99c|=99|a-c| test for every value |a-c| can have (1,2,...,8) the sum of the digits will always be 18

[@seersam]

yep knew it Just a small mistake. |a-c| can also be 9

[@Ulilopz]

Sorry, I picked 460 Maybe you should add a restriction to the picking part.

[@randomusername3445]

Víctor Ulises López Arias that still works 460-64=396. 3+9+6=18.

[@deanyona6246]

1+8=9

[@Ulilopz]

Thank you! I definitely misunderstand the instructions.

[@fk319fk]

I thought this was a different problem. Take a three digit number as stated, and subtract. Then take the result and reverse it again and add the two numbers. The number always is 1089, and I am not sure why.

[@TuberTugger]

So, choose a number from the follow series: 198, 297, 396, 495. Then add the digits together. Get ready to be impressed!

[@wolfgangsullifire6158]

I like the explanation and how you can work to get the answer

[@robylopezvi]

133 VIEWS?? IV'E NEVER BEEN THAT EARLY!

[@mehreenkhan6976]

I am 2 years late

[@robylopezvi]

Mehreen Khan lmaoo

[@eabhalindsay7469]

He was wrong I got 5 and I did the math right

[@paulobouhid6648]

You don´t need to *reverse* the order of the digits of the original number. Just write a different number with the *same digits* ...

[@ilyasabadashev958]

instead of adding up the digits, reverse your answer once again and sum those two... you'll get 1089 every time, i used that a lot as a magic trick :D

[@badrunna-im]

Ilya Sabadashev unless they picked 2_1, because no one reads 99 as 099.

[@purpleice2343]

99 is the same as 099... But okay, I don't blame you that you never had to play games as a kid... Most of the time, arcade ones have like 10 digit score which always has 0's in front of your actual score, always making it a 10 digit score even if number is a lot lower :)

[@x_abyss]

I used similar approach up until checking if every possibility sums up to 18. We know that the subtraction of the larger number from the smaller one is a multiple of 99, which means all the digits of the result add up to a multiples of 9, and the sum of the 1st and 3rd digits minus the 2nd is a product of 11. The only way the latter criteria can be satisfied is if 1st digit + 3rd digit - 2nd digit equals 0, meaning that the sum of the difference is even. Therefore the only sum of any three digits number divisible by both 2 and 9 are either 0 or 18.

[@RinkuTiwari232]

Great trick

[@ethanmemelord2727]

Ive known this trick for years

[@peter_castle]

Solution should have include, to be more trustworthy and not rely on summing all the last 3 digits numbers showed at the end, 1) sum of digits of the sbutraction is multiple of 9, because the substraction is multiple of 9, because both numbers have the same sum of digitis because of being reverse of each other thus having same digits, so the possible values are 0,9,18,27... 27 is 999 only which is clearly impossible, 2)prove the 2nd digit must be 9, to imply the sum of digits cant be 9, so its 18

[@saraflint2982]

I knew the trick as soon as you said "reverse the digits and subtract." This also works with 4-digit numbers. With 5 and 6-digit numbers, the end sum is 27. With double-digit numbers, the end sum is 9. (With single-digit numbers, the end sum is also 9. Example: 70 - 07 = 63. 6 + 3 = 9.) Good trick for beginners, but I'm onto you now!

[@shannonklotz6147]

I misunderstood what you meant by larger number. I was thinking 345 then switch to 543 and subtracted 3 from 5

[@cartbox8598]

No you have to subtract 345 from 543

[@bladecup]

@@cartbox8598 Why you dont give us example,tnx

[@dxmobile]

My answer was 12

[@owens020]

3 digets 222 reverse number 222 sutract the smaller number from the larger number 220 out math

[@greenmoonn1379]

I’m confused how do I subtract the smaller with the larger then add the result... bruh I’m confused

[@guinereyes9250]

Yeah.. Me too, that was the step I was wrong

[@ntwede]

Add up the digits of the result. Like with 254 you would do 2+5+4=11

[@christopherreese4546]

Yes.

[@ieatcaribou7852]

My number was 120. My answer was 3. Would any number with a zero in it mess this up I wonder?

[@user-nu6ge7px7s]

120-021 it mean 120-21 = 99 9+9 = 18

[@samarbhandari2196]

Brilliant

[@alloosworld1235]

My answer was 198

[@AQxJM]

I got 4 lmao

[@sourabhkukreja7543]

fantastic

[@MrHawkeyefan4life]

Wait how's this trick work? I'm not understanding this?

[@giladzxc17]

What happened to the time when you posted real riddles?

[@Kino-Imsureq]

Works with 4 digits too!

[@sunderlal3140]

You are correct

[@Kino-Imsureq]

0:39 I was looking at a number AKA 2.718281828459045 AKA e so yah

[@stellaquinn431]

No, I got 10, you used 100+10+1 Which that would be 111( one hundred eleven) the number I used was 587 (five - hundred eighty - seven)

[@AhmedMohamed-yr3nd]

Ooh..super true

[@keyurmakwana5973]

If we use all the three digit same the answer will always be zero

[@naret03]

Instructions unclear or maybe i'm dumb but i got 4. I chose 213 so i get 312 then i subtracted the largest number minus the smallest which is 3 - 1 = 2 then i added this result plus the digit i got left which is 2; 2+2 = 4... didn't know i was making two different numbers i thought i was changing my original number...

[@user-nu6ge7px7s]

It mean 213 reverse to 312 You need to subtract this before plus the single digit It must use the larger number to subtract he smaller number 312-213 = 99 9+9 = 18

[@anas-yo2zo]

I chose 1.23 🤔

[@mapledoctor3915]

32.1 - 1.23 = 30.87 3 + 0 + 8 + 7 = 18

[@idkdude27]

Picked 890 for first one and got 1/10

[@clementbisson6607]

did you notice the digits of 99n add up to 18 for n smaller than 100

[@lw8420]

But what about pi times 99

[@anthonygilroy9976]

I check and got 4

[@powertube5671]

Thanks! Very cool! At this date 342 people have clicked off the (I don't understand the math so I can never understand the trick and I'm never going to try to learn, thumb).

[@adamninjagaming9885]

I am in today in 6 class but my friend has done this trick on me at class 4

[@vickyduggal2799]

That is amazing

[@theepictalon8824]

YOU GOT MY NUMBER WRONG IT IS 6😅😅😅😅😅😅😅😅

[@usurper1091]

Please stop making these click baity tivial videos! I never subscribed for this...

[@gavinlourenco9842]

Ha, I chose 1.86 I got 14

[@900ml5]

Are you running out of content?

[@Sid-ix5qr]

Genius!

[@seemadhakad19]

Bro it's simple method Every 3 different number's sum was 18😒

[@bestofcricket3531]

amazing

[@saryustar61]

100 true video ❤❤❤❤❤❤❤❤❤❤❤

[@NetAndyCz]

18 is not even 3 digit number, mine was 123:p I hate this prediction "magic" which either reveals what you predicted after you revealed it, or predicts somnething completely else and makes you change what you thought or picked. Do nto get me wrong there is neat mathematic involved in this, but do not try to make magic trick out of it, it is not a good one and in this case I am afraid average Joe will make mistake when performing subtraction without calculator or piece of paper, which will ruin the trick:D

[@purpleice2343]

The magic in there is that people who have functioning braincells will get 18, and braindead retards will fail to do so.

[@jameskelly-smith1279]

Okay, who else chose the three digit number 420?

[@Sir.BlackHole]

0:09 ok you never specified if it has to be a whole number or a decimal one... so i will pick 3,14 (it's 3 numbers and they are different from eachothers) mh... from 3,14 to 3,41 ok now i have 0,27 0 + 2 + 7 = 9 naw bro NOT EVEN CLOSE hahahah 0:41 no... you failed again... also with the other "i will predict" you failed... 0:47 cap. I followed them BUT you NEVER specified if the number was meant to be decimal or not. I picked up 3 different numbers... i followed the rules. recheck my math??? bro 3,41 - 3,14 = 0,27 and 0 + 2 + 7 = 9 not 18 0:54 no. At least... not with me. 1:26 you never specified if we had to do with all of them... or just 2 of them... so i chose to reverse only 2 of them.

[@samaiahgames9949]

Didnt work

[@faisaldaquigan8465]

Mine is 17 and his is 18 but I did it correctly

[@bladecup]

Started with 357 and reverse order 753,so i got 45,or i screw some of your math...

[@De_Lune8002]

How'd you get 45??

[@ethanlee7163]

You did not guest mine correctly mine was 5

[@Andrea-ln2ti]

So this is math class

[@mojobouji]

Mine was 22 😮😯

[@Riiisuu]

Upload. Real. Math.

[@lare290]

This. Fuck these dumb tricks that are basically "I'll guess your birthday. Take your birthday, subtract one and add one day. That is your birthday, pretty cool huh?"

[@LesIsMoreFilms]

The. Real. Math. Is. In. The. Proof. You. Fart.

[@lare290]

The proof is just basic algebra though.

[@LesIsMoreFilms]

Perunavallankumous it's algebra but definitely not "basic" algebra. I doubt you knew the proof the moment you heard the question presented

[@yazan.kioumgi]

Thumbs down because you didn't show why the digits of 99(a-c) will always sum up to 18. Listing all possibilities is a weak solution.

[@marinamacri5520]

All digits of numbers divisible by nine add up to a multiple of nine that is under 90. Because the number is always a multiple of 9 and probably some distance that is a multiple of some number away from another number, it will always add up to 18

[@master-sj6cd]

Ok i haven't seen the solution, but here's my way of answering, let s(n) be the sum of n's digits, it is known that s(n)=n (mod9) so with this we can say for sure that the answer is a multiple of 9, (both numbers have the same digit sum) then since we looking for the difference between 2 numbers without common digits we could express this as abc and cba being the numbers (you know what i mean i don't know the english word for that) then i forgot how i proved the last part where i prove 18 fuck me

[@dragan176]

Hey, I managed to do this one :D

[@impossiblephysix2633]

I took 120 is this legal

[@mohammadebrahimi2871]

My number was 333

[@qamartajqamartaj8694]

123

[@rushildev9874]

Got 11 dude (Edit = no I got 18 wow )

[@adipocere5487graphomet]

I did 434, i got 0 as a result

[@anitamcsd1]

Shannon Wood hey did you know that you can pick a number with different digits. It's better. CAUSE THAT IS WHAT THE QUESTION ASKED.

[@anitamcsd1]

Shannon Wood man I wonder why he said a number with THREE DIFFERENT DIGITS

[@GeneralAkAbA]

It doesn't work...

[@sheryl-leeanderson-shaw7006]

I got 8

[@mosshotep]

My number was 000

[@prasantaonline]

Yes u R

[@MrWadood007]

Yeah, doesn't work when a=c.

[@wunderapple8009]

Lmao I got 17

[@rico666six7]

You didn't get mine

[@Urawizardharryy]

I got 22

[@alexlin750]

i took 012 and didn't work

[@theoreticalstranger4339]

210-012 =198 1+9+8=18

[@alexlin750]

oh thanks xd

[@leabertuzzi518]

I got 15 and my boyfriend 13 lol

[@hamza_shafi2748]

10

[@rodjegilpunzalan3318]

my number is 9

[@rodjegilpunzalan3318]

me to

[@Nostalgiachannel1]

No 99

[@chixenlegjo]

875 578 8-5=3 3+7=10

[@user-nu6ge7px7s]

875-578 = 297 2+9+7 = 18

[@ranjitkumarsarma4906]

Okay