Alex Bellos demonstrates a very cool, and strange way to multiply

[legggggggggy]

Im better than all of you. I use a calculator.

[slippyfist2405]

This method only works with certain numbers.....pretty pointless generally

[Compiteision]

esoo si es eficazz

[bizzwoofer]

black people smell. Im sure they all get together while the almighty white people rest their obviously angelic heads at night - and have the STANKEST BUTTFUCK ORGY EVER!!!! everyone knows that smelly NIGLETS are pieces of shit that wanna suck cock, even though they have one themselves.. black people are gay, is pretty much what im trying to say here (for you dumb niggers who cant understand.) I wish they would all go starve and catch aids untile they are gone fore goood! praise ALLAH, faggots.

[MsMimo70]

Meu lindo Alex uma simpatia.

[LordHexer]

srsly...multiplying in head is way faster

[StaefNguyen]

@LordHexer Multiply 123 and 312. In your head.

[HeyItzMeDawg]

@StaefNguyen Easy.  Most humans who work with math on a regular basis can multiply and divide 1 to 5 digit numbers. Just break up an n*n digit question into a series of n*1 digit questions (which are very simple) and add the results together.

E.g Break it into 123*2 (=246) + 123*10 (=1230) + 123*300 (= 36900); add up the three results and you're done. Working with digits one at a time means your only limitation is your memory (of the question and your partial results).

[fahod0567]

this is supposed to be the best algorithm for right-brained students, and yes it is.

[vixpatel1991]

@strawberry00cookie it was created by Indians from India. not American Indians lol

[strawberry00cookie]

what's the origin of this multiplying style? need it on a report.. :/

[BananaBean03]

zomg, my math teacher wont let us use calcs on tests and you just saved me from failure. u da man

[Drei216]

Anyone can tell me the title of the background music? Interesting video by the way.

[SpaceApe2k]

@Drei216 Chopin's "Grande valse brillante"

[SwampIg2]

This is quite clever and visual, but really it's identical to long multiplication. 3 lines will cross 4 lines 12 times. Add up the rows and there you are.

[Telmata]

really nice

[PieceOK]

how do you handle with a zero at the end? I don't know how to draw this

[xanfsnark]

@PieceOK Don't: for something like 730 x 1100, multiply 73 and 11, then multiply the result by 1000 (i.e. add three zeros to your answer).

If you have a zero in the middle, maybe use a light or dotted or wavy line, and don't count those dots.

[50srefugee]

OK, now do it with something like 768 x 957.

It's an interesting demonstration of what the numbers represent-- but doesn't strike me as being practical.

You know what is practical? Drilling third through fifth graders for half an hour every day with flash cards. Giving them a hundred long division problems to do over Christmas vacation. Daily quizzing. Practice, practice, practice.

It's boring, it's dull, it instills self-discipline, it works.

Think of it as a kind of meditation.

[Oplem]

@50srefugee i agree that drilling the tried and tested algorithms are the quickest way to learning how to solve these problems, but activities such as this are designed to develop number sense and an understanding of what you're doing when you're multiplying/dividing.

for example, the long division algorithm is just a strategy that works. using that method will get you the right answer through a shortcut that makes no sense mathematically.

[Oplem]

@50srefugee it's important to do both of these in the classroom, not just one or the other.

[theflubba]

@50srefugee Yes that is practical, but that way the kids are just memorizing things, and not truly learning or understanding the reasons behind the answers - they aren't truly learning anything useful if they are just blindly doing exercises and memorizing trivial multiplications.

[johnnykingg]

This really cool. For my first attempt I tried 296 x 4157 (random)... now I know why it hasn't caught on!

[chiffmonkey]

@johnnykingg Jesus that's not easy

[saomkinar]

@johnnykingg I did the same calculation that you did....even though I came out with the correct answer 1,230,474, it took me 10 minutes to do it the Japanese Way, in which it took me 1 min 10 sec to do it the old fashion American long multiplication way......The only difference is that in the Japanese way there is no Multiplication needed, only addition. But you are adding up some big numbers though....

[RiaceWarrior]

@johnnykingg

Try the simplest! 7x8 and realize how stupid the method is!