Number Trick - NumberphileYouTube↗  IA↗(long shot)
Science & Technology  1.7M views 21.5K likes 1.3K dislikes   02 Jun 2013
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Spanish Javier Wagner
MATECLIPS
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DR. JAMES GRIME: So we're going to do a little
DR. JAMES GRIME: stiamo per vedere un piccolo
mathematical trick that I'm hoping that people will like and they'll try out on their friends and family. So let's do it.
trucco matematico che spero piacerà a molte persone 4 00:00:06,030 --> 00:00:09,060 e che lo ripropongano a loro volta a familiari e amici 5 00:00:09,060 --> 00:00:10,890 Quindi cominciamo
We're going to write out four-digit numbers. So like this, right? Now, you've got 3,485, but we'll take it in turns. So give me a four-digit number.
Dobbiamo scrivere numeri di quattro cifre 7 00:00:14,530 --> 00:00:15,680 Ad esempio come questo 8 00:00:15,680 --> 00:00:21,480 Ora abbiamo 3.845, ma li prenderemo in più turni 9 00:00:21,480 --> 00:00:23,770 Quindi prendiamo un numero di quattro cifre 10 00:00:23,770 --> 00:00:26,280 Se vuoi puoi anche pensare solo a quattro cifre
You could just shout out four digits if you want.
Go on. BRADY HARAN: You want one from me? DR. JAMES GRIME: Yeah. BRADY HARAN: 7,721.
Dimmelo 12 00:00:26,935 --> 00:00:27,786 BRADY HARAN: Vuoi che io te ne dica uno? 13 00:00:27,786 --> 00:00:28,132 DR. JAMES GRIME: Sì 14 00:00:28,132 --> 00:00:30,530 BRADY HARAN: 7.721.
DR. JAMES GRIME: 7,721.
DR. JAMES GRIME: 7.721.
And now I'll come up with a different one, like 2,278.
E io adesso ne dirò un altro, come 2.278.
Give me another. BRADY HARAN: 1,891.
Dimmene un altro 18 00:00:39,953 --> 00:00:42,368 BRADY HARAN: 1.891.
DR. JAMES GRIME: 1,891.
DR. JAMES GRIME: 1.891.
And I'll come up with another one, like 8, 1-- something--
E io adesso dirò 8.1... 21 00:00:49,400 --> 00:00:50,645 qualcosa... 22 00:00:50,645 --> 00:00:51,330 8.
8. And we're going to add these together. 3,485, 7,721, 8, 1-- and 8, there you go.
E adesso li sommiamo tutti 24 00:00:54,970 --> 00:01:02,101 3.485, 7.721, 8.1... 25 00:01:02,101 --> 00:01:03,532 and 8, ed eccoci 26 00:01:03,532 --> 00:01:04,720 Quindi ecco cosa abbiamo qui 27 00:01:04,720 --> 00:01:06,980 Vediamo quale è la risposta 28 00:01:06,980 --> 00:01:12,840 Bene, quindi la risposta finale è 23.483.
So we see what that is. Let's see what the answer is. OK, so the final answer is 23,483.
Now, before I started the trick, I made a prediction on that strip of brown paper.
Ora, prima che iniziassimo il trucco io ho fatto una predizione 30 00:01:18,120 --> 00:01:20,300 su quella striscia di carta marrone 31 00:01:20,300 --> 00:01:21,690 Diamoci un'occhiata
Let's have a look. Let's have a look at my prediction.
Diamo un'occhiata alla mia predizione
If I open up my prediction, it says, I predict 23,483.
Se apro la mia predizione, trovo scritto che ho predetto 23,483.
And then I think what you're meant to say here is tra-da!
E quindi penso che quello che vorresti dire sarebbe ta-da!
Do you want to see how to do it?
Vuoi che ti dica come ho fatto?
Shall we learn how to do it?
Potremo imparare come si fa?
All right, and then people can do it to
Bene, così anche le alte persone potranno farlo 38 00:01:44,410 --> 00:01:45,780 ai loro amici
their friends, as well. Did you notice I started it off?
Hai notato che ho cominciato io?
So I picked a number to begin with. Then you picked a number. Then the number I picked after you-- and we took it in turns--
Ho scelto io un numero con cui cominciare 41 00:01:50,200 --> 00:01:52,070 Poi hai scelto tu un numero 42 00:01:52,070 --> 00:01:53,830 Poi ho scelto io un numero dopo te... e 43 00:01:53,830 --> 00:01:55,310 Noi li abbiamo scelti a turno 44 00:01:55,310 --> 00:02:00,950 E io ho scelto il numero in modo che le sue cifre sommate a quelle del tuo dessero 9.
remember, I picked the digits column by column add up to 9.
So 7 and 2, 7 and 2, 2 and 7, 1 and 8. So these two together are equal to 9,999. The next two rows, I did the same thing. Can you see?
7 e 2. , 7 e 2, 2 e 7, 1 e 8 46 00:02:04,930 --> 00:02:11,820 Quindi questi due sommati equivalgono a 9.999 47 00:02:11,820 --> 00:02:14,270 Ho fatto la stessa cosa anche per le due righe successive 48 00:02:14,270 --> 00:02:15,150 Vedi? 49 00:02:15,150 --> 00:02:15,995 Sommate danno 9
They add up to 9. I had the 0 there when you picked the 9. And that's 9,999. So the last four rows together are going to be just shy--
Ho scelto 0 quanto tu hai scelto 9 51 00:02:18,340 --> 00:02:21,780 Ancora 9.999 52 00:02:21,780 --> 00:02:26,810 Quindi le ultime quattro righe sommate fanno quasi 53 00:02:26,810 --> 00:02:29,004 Beh, è proprio quasi 10.000
well, this is just shy of 10,000.
Add them together. It's just shy of 20,000.
Sommiamole 55 00:02:30,220 --> 00:02:32,050 E' poco meno di 20.000
It's 2 short. It's 19,998. So I knew that the last four numbers were 19,998.
Meno di 2 57 00:02:33,570 --> 00:02:37,470 E' 19.998 58 00:02:37,470 --> 00:02:43,920 Quindi io sapevo che gli ultimi numeri avrebbero dato 19.998.
So what I did to make the prediction-- I had thought of this in advance.
Quindi quello che ho fatto per avere la previsione 60 00:02:46,670 --> 00:02:48,680 E' stato pensare a questo in anticipo
And then I added 20,000 to it, which is quite easy to do, because you put the digit 2 at the beginning. And then because it's 2 less than 20,000, I subtract the number 2.
E aggiungere 20.000, che è abbastanza semplice da fare 62 00:02:52,110 --> 00:02:55,290 Perché metti la cifra 2 all'inizio 63 00:02:55,290 --> 00:02:58,000 E poi, visto che è 20.000 meno 2 io 64 00:02:58,000 --> 00:03:00,240 Ho sottratto il numero 2 65 00:03:00,240 --> 00:03:02,520 Quindi tu metti la cifra 2 all'inizio 66 00:03:02,520 --> 00:03:06,740 E sottrai 2 alla fine.
So you put the digit 2 at the start. And then you subtract 2 from the end.
And you can make your prediction. And you can look like a mathematical genius.
E tu puoi fare la tua previsione 68 00:03:08,550 --> 00:03:11,410 E puoi sembrare un genio matematico 69 00:03:11,410 --> 00:03:12,610 MATT PARKER: Torniamo alla carta scelta
MATT PARKER: Back to the chosen card. You're just not going to get far enough. But what you will do is you'll take off, well, let's say 12.
Non bisogna discostarsi di molto 71 00:03:13,990 --> 00:03:16,233 Ma quello che farai è scartarne, diciamo 12.
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12.
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12.
And then obviously you're going to do the thing with,
E quindi poi farai ovviamente la cosa del...
oh, no, that's not it, it didn't work, boo hoo.
Oh no, non così, non ha funzionato boo hoo.
The trick now is, instead of putting these back on top, put them underneath.
Il trucco adesso è che invece di metterle sopra, si mettono 76 00:03:28,200 --> 00:03:29,450 sotto 77 00:03:29,450 --> 00:03:29,660
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