Stacked Dice Trick - Numberphile

A third dice trick with Ben Sparks - see the trilogy of tricks at: bit.ly/Dice_Trilogy
More links & stuff in full description below ↓↓↓
Ben Sparks: www.bensparks.co.uk
And his KZbin: / sparksmaths
More Ben Sparks on Numberphile: bit.ly/Sparks_Playlist
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[@oafkad]

16+2 is 18. "17!" His confidence is what makes it for me.

[@amative1]

Parker Arithmetic

[@felipevasconcelos6736]

Reminds me of the song “Dezessete e Setecentos”, where the speaker insists 20 000-3 300 = 17 700, and brags about his superior education when questioned.

[@thesuomi8550]

r/unexpectedfactioral

[@davidiverson5928]

For sufficiently small values of 16 and 2... Round(15.7) + Round(1.7) = Round(17.4)

[@albertmaheswara9968]

That's like asking "What's 9+10 ?"

[@kallewirsch2263]

After having to apologize for the 3d time for having turned to soon, it becomes somewhat suspicious.

[@MrCheeze]

For a magician, it's important to always have a backup trick on hand... people will ask you to see something again, and instead of brushing them off you move on to the next trick.

[@ShirHac]

Never do the same trick twice.

[@Tombsar]

Once is a trick, twice is a tutorial.

[@shruggzdastr8-facedclown]

Killer closing line from Ben!!: "Is that so unusual?"

[@Triantalex]

false.

[@jasonbraun127]

The interesting thing is: I 100% noticed his look but I thought "Well, the looking away bit is purely theatrics anyway and he probably already knows the total number because of math so it likely was actually accidental." The reveal that he had to look to figure out the top number sounds kind of cheap when you say it out loud but it genuinely surprised me. I guess I'm more naive than I thought I would be.

[@SolitaryCZ]

I like it, the misdirection disguising the actual "magic" trick by pretending to be a "smart" (calculation) trick is pretty unexpected (for this channel). It aims to trick people who know their dice and the properties and immediately started thinking about 7s and tried to figure it out, but the trick is impossible without the peek.

[@Vallam23]

it works because you think "there's no way he looked long enough to remember the position of all the die in the stack" and dismiss it before you even start working it out

[@Triantalex]

??.

[@vojtechstrnad1]

The animations have really come a long way.

[@hemanthsai4584]

that's blender

[@iseriver3982]

You're telling me, I thought they were real dice until they literally flew off the table.

[@zlosliwa_menda]

Yes, I'm especially impressed by the animation of Ben Sparks throughout the video. It looks almost like the real guy.

[@matttondr9282]

To teda!

[@Triantalex]

false.

[@lekmannen9990]

Next Numberphile video: 16 + 2 = ?

[@FilmscoreMetaler]

-1/12

[@LukeSumIpsePatremTe]

Parker's dozen

[@columbus8myhw]

20-ish? 15-ish?

[@lekmannen9990]

@@columbus8myhw we will never know

[@FanTazTiCxD]

*sEvEnTAIN*

[@kirenireves]

Since there are only 6 possible answers (20 -15 inclusive) another interesting reveal would be to have 6 slips of paper in his pocketses. One in each back pocket, one in each front pocket, one in the coin pocket of his jeans, and the last one in his shirt pocket. Then he can simply pull out the correct slip of paper with the answer written beforehand. ^_^

[@ZachGatesHere]

Ben Sparks just makes everything super engaging and fun. Love this guy. Also, I think keeping a reveal in different pockets might work? Like, having paper with the number written on it or something else that feels more deliberate than coins.

[@IceMetalPunk]

Only works if you have 6 pockets. Most of my pants only have 4 :D

[@snuffysam]

@@IceMetalPunk There’s ways to work around that. Tear the six papers into slightly different shapes so you can distinguish them by touch.

[@yashrawat9409]

3 Stacked Dice ~Invariant~ 2:45 - Can't have a Numberphile Video without embarassing mental arithmetic

[@muckerwood]

The last line about 21 pennys in his pocket, "is that so unusual?", isn't any more unusual than having 20 pennys, which is what he SHOULD have had in his pocket for this particular trick.

[@Vallam23]

a nickel, a dime and 5 pennies

[@muckerwood]

@@Vallam23 or 2 dimes and a Bob Uecker rookie card.

[@gormster]

But what if the zero comes up?

[@Formulka]

that peek seemed really natural, well done

[@SnapquesterMage]

"Is that unusual?" 🤷‍♂️😅

[@ASIMOfb]

and the perfect frame to end the video on.

[@Wecoc1]

"Perfectly cut existential crisis"

[@datkidd4700]

If you like this video , you’ll probably like Seven Hunnid, i watch him alot on KZbin

[@Wecoc1]

I always carry a note that says "This wasn't an accident, I was killed", in case I have an accident.

[@PhilBagels]

It's not unusual to count to twenty-one (ba-da-da-da-da-da) It's not unusual to stack dice for anyone But if I guess the total of the hidden sides It's not unusual - cause I watch numberphile!

[@Farquaad3rd]

This man will not stop until every dice trick has been mastered.

[@loganv0410]

As a (now retired) math(s) teacher I love the applicability to teaching the Associative Law

[@friggelflander2558]

Literally a channel about maths and numbers Also the channel: 16 + 2 = 17 Even the best are just human and make mistakes from time to time :D

[@cadekachelmeier7251]

That's why they invite Matt Parker on the channel.

[@stevenverhaegen8729]

@@cadekachelmeier7251 Was going to make a Parker comment too. 😂

[@visionandimage5893]

Mathematics is not about being a calculator though

[@friggelflander2558]

@@visionandimage5893 Yes, maths all about knowing how to use a calculator /s

[@lonestarr1490]

@@friggelflander2558 So, what is math actually about? Inventing _new_ calculators! (For things the old ones couldn't solve, of course.)

[@JKVeganAbroad]

Honestly Ben Sparks is the most handsome celebrity on Numberphile, just looking at him makes my heart melt… every… time 😍😍😍

[@ig2d]

might be interesting to do a numberphile video on the olympic scoring system for sports climbing. The competitors position in each of three disciplines were multiplied together with the lowest score winning the highest score losing. Why dud they choose to multiply instead of add.

[@QuantumHistorian]

Because multiplication is scale independent. You can rescale any of the events individually in any linear way and the order of their products wouldn't change. It's far more stable than addition in that sense.

[@ig2d]

@@QuantumHistorian now that's what I'm talking about! (thanks) - though I still reckon it's worth a Numberphile video. When the very last competitor (Jacob Schubert) was completing the final discipline and climbing himself up to a bronze medal position - while he was doing it the placing of all the other competitors kept shuffling around like a deck of cards. 🙂 Adam Ondra, for example, went from outside the medals to gold, back down to outside the medals again.

[@garrick3727]

@@ig2d The rapid changes in position sound like another reason to do it. With addition it's easier to get into the situation where the last round is something of a foregone conclusion: some people cannot win, some people are very likely to win. With multiplication the scores are more volatile, which makes the last event just as important. What you see in many sports with additive scores, like golf, is that it's easy to get into a situation where you have a lead, or you are so far behind you cannot win. They have a cut precisely to remove people who are unlikely to win, and people with a lead often play safe, such that the person leading going into the last day wins the tournament 50% of the time. You could still have a safe lead with multiplicative scores, it's just less likely.

[@ig2d]

The most striking example: Mawem in the qualifying round of 20 came 1st in the speed, 18th in bouldering and 20th (last) in lead totalling 39 out of 60 by addition but 360 by multiplication. His multiplication total earned him 7th place out of 20 and therefore a top eight qualification to the final If you compare the climbers totals by addition - only the bottom three competitors of the 20 had a higher total. By addition he would have come joint 16th (tied with Jan Hjoer)

[@flashpeter625]

I think a key point is that they did not want to have the 8 best universal climbers in the final. Those would be mostly less known climbers (because combined events do not normally exist), and this Olympic competition was very much about promotion of the sport for the future. I think they really wanted to have the well-known stars of the individual disciplines in the final. And in the multiplicatory score system, placing high in a discipline (and especially winning) is disproportionately advantageous. The winners of the individual disciplines were almost guaranteed to go into the final even if they were mediocre in the other 2 disciplines.

[@AliKhanMaths]

This is such a great video! Videos like yours inspire me to share my own maths content!

[@littlefermat]

Well, the expected value of the answer is 17.5 If I were to do this trick without peeking at the dices... I will tell each one of my students to do it separately, then I will ask them to evaluate the mean of their answers, and hopefully the mean will be close to 17.5😉 Proof for the Ex: E(X+7+7) = E(X)+14 = 3.5+14 = 17.5

[@3c3k]

r/iamverysmart

[@EebstertheGreat]

Similarly, Var[X+7+7] = Var[X] = (6²-1)/(12*6) = 35/72. If you have n students perform the experiment, the variance is Var[sum(X)/n] = 1/n² sum(Var[X]) = 35/(72n). That's a standard deviation of √ (35/(72n)) = 0.6972/√ (n). So for instance, with n = 20, the standard deviation is only about 0.1559. It seems pretty reliable.

[@3c3k]

@O K he said the most obvious thing ever

[@float32]

@@3c3k “he said the most obvious thing ever”? Talk about /r/iamverysmart…

[@V_2077]

@@float32 got him 😂

[@VAXHeadroom]

The ending was worth the WHOLE setup! :D

[@F1fan4eva]

5:30 Where do you teach Ben. Your students are lucky! There is not a single video of yours on Numberphile that hasn't blown my mind and where I'm not smiling like an idiot by the end.

[@please.dont.]

glad i’ve seen today’s vi hart’s video, so i know about opposite sides adding up and am therefore immune to this tomfoolery

[@_abdul]

16 + 2 = 17. I've seen that on Numberphile. So, your argument is irrelevant.

[@stevenverhaegen8729]

Remember the trouble they got when claiming 1+2+3+...=-1/12 😂

[@Inspirator_AG112]

For any stack of *n* dice with any number *t* (being 1 to 6) on the top of the stack, it is possible to calculate the sum of all tops & bottoms of each die (excluding the top) with just *7n - t.*

[@TheDetonadoBR]

The moment he turned around by accident I knew he was up too something cheeky hehe

[@Ovetupp]

As an avid boardgamer, I love these dice videos. I am willing to use any and all forms of trickery to mess with my opponents!

[@johnchessant3012]

But as we learned from Vi Hart yesterday, this trick might not work for all octahedral dice

[@andreashofmann4556]

The bowl standing over the edge of the table upsets me.

[@Eduarodi]

"I didn't cheat in my exam. I just did some magic".

[@Questerer]

Although I knew this trick from my childhood, I loved this video. (I had a fun teacher as well)

[@angelodiavolo3915]

"But it's 19..." "Bro." Killed me 🤣

[@Tomapella]

that 18 just hanging around taunting him is a nice touch XD

[@BradSchmor]

The periodic table on the wall (showing 104-106 as Unq, Unp, and ending at Unh) has to be the most widely produced version ever. Fisher Scientific, mid-1980s vintage. I still have a notebook-sized copy.

[@KuroroSama42]

The second he started adding up the faces I knew what the trick was. 21 minus the top. Super obvious. The difficult part was with the premise. He said he should have had the hat cover it. CONSIDERING YOU SHOULDN'T SEE THE TOP, I couldn't see a way to know what the total is. I kept thinking "well he has to break the premise and see the top, right?"

[@AbhijeetSingh-rs5qb]

Woww the very first vedio I watched on this channel and boom subscribed🔥🙌

[@SecretSquirrelFun]

I like the idea of using magic as a way of teaching. Thanks for sharing this video. Oh yeah, while I’m here - Aussie tv ad for Blinkist app has “Thinking Fast and Slow” as the book title on the actor’s phone screen. I just sat there shouting Nooooooooo at the screen.

[@realnikb]

Stand up maths had this trick a few years ago, that’s how I learnt it always multiples of 7s based on the number of dice!

[@BlaqueT]

What a fun trick! Have to pull this one out at parties

[@Veptis]

I had that thumbnail in my watch later playlist for nearly 90 days. And I expected it to be something 21 related.

[@hyfy-tr2jy]

In homage to our resident "Maximus the Mathematician"....I am entertained!

[@mihailtsvetkov4011]

4:05 I KNEW IT!

[@marcelocampos665]

Would you please make a video to explain why if we have an integer, and we want to find a sum sequence inside it (for example: 9=2+3+4=4+5; or 10=1+2+3+4); the amount of solutions for a given number is related to its prime factors? (2^n has no solutions.)

[@fredrodriguez3913]

Can you make a video about those “hyperbolic marble funnels?” Are they actually hyperbolas? What is the theoretically most efficient design?

[@singerofsongs468]

Two videos in two days about dice! One from the lovely Vi Hart, and one from Numberphile! Always a pleasure :)

[@LudosErgoSum]

A more clever way without any peeking necessary would be to have your volunteer add up the numbers as described THEN have them subtract the top digit. Then you can reveal the top digit as THE MAGIC TRICK with 100% confidence.

[@LudosErgoSum]

@@Matt_6.6260 Yes, the sum of all three dice is 21, but the sum of the proposed operation in the video is 14+b which leaves out the top as the unknown variable. By having your volunteer subtract the top from the sum of the previous operation, you can deduce the top digit with 100% confidence because there's only 6 possible outcomes that are unique. Here''s the breakdown of possible sums: 14+b-t 14+1-6=9 => TOP=6 14+2-5=11 => TOP=5 14+3-4=13 => TOP=4 14+4-3=15 => TOP=3 14+5-2=17 => TOP=2 14+6-1=19 => TOP=1 I think you read something wrong because I clearly stated that the volunteer includes all the dice faces and then state the sum i.e. forcing the number and giving you the key to figure out the top digit (and bottom digit as well). There's no need to assume that there is a variable since you have all the information you need to discern the top digit which is the magic trick here (not the sum of the dice as in the video which also rely on you spotting the top dice).

[@MathProfessorKyleMartin]

Awesome!!

[@tejas8719]

This guy would be the life of his pub!

[@dfmayes]

I like the videos that I have a shot at knowing the answer.

[@shreeyamittal1771]

I'm just surprised he didn't knock the bowl off the table all this while, it's so damn close to the edge.

[@SledgerFromTDS.]

Great video by Numberphile to Say, There's other Videos that you can make

[@AnkitShivayFact]

Nice video sir ji

[@RobertBallMagician]

Nicely done 😊😊

[@frankharr9466]

That's quite a trick. And it relies on subverting the expectation that it's not "tricksy". :)

[@Koisheep]

i will use my trusty numberphile cap™ edit: now here's a lesson in trickery

[@stevefrandsen7897]

Ben is cool. And smart!

[@Jintero]

Your Old Video 301 this is world record video love from India

[@lastSKYsamurai]

Pretty cool!

[@wise_math]

I tried this with a friend and he was surprised.

[@filipmilovanovic8942]

You throw 18 coins on the table, and walk away proudly, waiting for them to be impressed. -"Nah, mate, it's 17!" . . . . . . IN THE NEWS: Man arrested for starting a bar fight over a math problem.

[@sreedevm7668]

I think this guy is the one who buys 60 watermelons 😂

[@ddobrien1]

Dice Stack Cheat - Numberphile _Fixed the title for you._

[@nmpspiky]

My little 🥰 brothers and sisters I will be living forever in your hears 💕 by pulling this dice trick at family functions. 👪

[@kevina5337]

As soon as he sneakily checked the top of the dice I knew it was 21-(top number)

[@MrCheeze]

I wasn't paying attention for the sneaking and assumed he was going to be told 19 and predict the 2.

[@chattyw87]

Only need 20 coins, theres no way you can roll a zero

[@dakotathacker3821]

is the professor still alive? i recently rediscovered this channel amd gave a quick scroll and got to 2 years ago without seeing him. im just wondering about him.

[@hotmole7621]

nice

[@Willy_French]

you can make this better using a blindfold. say you roll two at random and stack them quickly. then say i will roll one pick it up press your thumb on the top and hand it to him. look down through the blindfold at the imprint on your thumb or after he covers it with the hat take the blindfold off and stroke your forhead to get the mental power goin and look at your thumb. if you have a hitchhikers thumb like me that bends all the way back. or take a drink and look at the thumb.

[@georgew.9663]

Hahaha great way to end the video

[@hitchikerspie]

16+2 = 17, Parker addition right there

[@EsEhKa]

Next time when you have to put something on the brown paper to hold it down, can you please use something other than a bowl that is so close to the edge of the table. Thank you!...

[@ShirHac]

"Is that unusual?" :D

[@NekuraCa]

Is this a reupload? I've seen this trick on here before

[@MonsieurBiga]

It's the third video with Ben and three dice.

[@Booskop.]

A cap spelling "Numberphile" covering a numberpile.

[@b22chris]

So you do 21 minus the top number to get the answer?

[@comma_thingy]

Yes

[@reidflemingworldstoughestm1394]

That was dicey.

[@guidoferri8683]

I feel betrayed

[@ddobrien1]

I'm unsubscribing.

[@RobertBallMagician]

New subscriber

[@AgentM124]

16+2= ... .. SEVENTEEN!!

[@stevethach3340]

Ohhhhhhhhhhhh theater and math

[@demontoarch]

Please help, I've been trying to find this, where in the world and for what reason do we use millions for 1000. I've been trying to Google it, but nothing.

[@Psi_Fan123]

Before he said its not allways 19 i was like hey wait a minute oppisite sides on regular dice add up to 7 and 7+7=14 so the top dice needs to be five on the bottem and two one the top

[@sayedfarmanhusain6216]

I have found something .. there is a possiblity of having a new perfect number between the 4th(i.e 8128) and 5th (i.e 33550336) perfect number.

[@General12th]

Have you now.

[@markuhler2664]

Oof, a little trouble with the addition. Nice trick though.

[@rohannavin6294]

Ft: Russel Crowe

[@helloworld-ru9tz]

now the real question is, how can we do the same trick with 'n' number of dices!

[@hugobouma]

Just 7n minus the top number, although keeping them stacked in the first place will then become the greater challenge.

[@facitenonvictimarum174]

I'm glad he's having fun, no one else is.

[@fep_ptcp883]

I guess you can't fool Penn & Teller with that, but ok...

[@hyfy-tr2jy]

I have a hunch the views for this video will be lower because it looks just like the last three dice trick thumbnail (same three dice)... I know I didn't click right away because of this

[@madingo5092]

Hi

[@TheGreatAtario]

Singular of "dice" is "die"

[@jakolu]

Sleight of head. Funny it took me a 2nd time watching the trick to figure it out…

[@Raj80008]

Op

[@NateCrownwell]

I knew how it was done before you said how it was done :)

[@1.4142]

Video title trick

[@haroldchesney1934]

MV rất hay, i like it 😚🤒😟

[@jr8209]

Sofa King Fun

[@psikk3408]

2+5=7 yeah. Unless I am missing something??

[@gsurfer04]

It's not unusual to be tricked by anyone!

[@rokerdrive]

My friend: So you're studying math, you must be like a calculator. Me: 2:57

[@ghahyunmin4683]

18!!!!!!