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Category: Misc
Date: 11/19/13 05:27 PM

31 Responses to How Japanese Children Learn To Multiply [Pic]

  1. Profile photo of ElectricEye
    ElectricEye Male 40-49
    2723 posts
    November 19, 2013 at 5:29 pm
    Link: How Japanese Children Learn To Multiply - Japan: Where even the math is weird.
  2. Profile photo of Verenthi
    Verenthi Male 18-29
    46 posts
    November 19, 2013 at 6:01 pm
    Looks like a different representation of what we do: multiply every digit of the first number with every digit of the second. But the way it makes it so visual is pretty neat indeed.
  3. Profile photo of FoolsPrussia
    FoolsPrussia Male 30-39
    3446 posts
    November 19, 2013 at 6:03 pm
    Aren`t children a little young to multiply?
  4. Profile photo of carmium
    carmium Female 50-59
    6381 posts
    November 19, 2013 at 6:04 pm
    That`s hardly what I would call a shortcut. 8-\
  5. Profile photo of bacon_pie
    bacon_pie Male 30-39
    3061 posts
    November 19, 2013 at 6:51 pm
    This sums it up.
  6. Profile photo of redofluke1
    redofluke1 Male 18-29
    26 posts
    November 19, 2013 at 7:01 pm
    FoolsPrussia: I don`t think he means that kind of multiply.
  7. Profile photo of drworm2002
    drworm2002 Male 30-39
    662 posts
    November 19, 2013 at 7:24 pm
    The calculator is Korean not Japanese.
  8. Profile photo of Magentab0b
    Magentab0b Female 30-39
    1467 posts
    November 19, 2013 at 8:40 pm
    I prefer long division and long multiplication when doing things by hand it`s easier/quicker for me to double check.
    In my head I prefer weird approximations or dealing with fractions.
  9. Profile photo of Draculya
    Draculya Male 40-49
    14544 posts
    November 19, 2013 at 8:41 pm
    We`ve covered this method here before
  10. Profile photo of Runemang
    Runemang Male 30-39
    2676 posts
    November 19, 2013 at 8:46 pm
    whoa.
  11. Profile photo of incubus_inc
    incubus_inc Male 18-29
    976 posts
    November 19, 2013 at 9:08 pm
    geomegebra. i love it.
  12. Profile photo of jinxiejae
    jinxiejae Female 30-39
    2928 posts
    November 19, 2013 at 10:22 pm
    wait...what? what the hell are the blobs even for?
    I cant...I dont even...what?
  13. Profile photo of whirlygirl
    whirlygirl Female 30-39
    230 posts
    November 19, 2013 at 10:42 pm
    I want to learn how to do this! Just... because.
  14. Profile photo of wolfguy423
    wolfguy423 Male 18-29
    172 posts
    November 19, 2013 at 11:42 pm
    this is extremely cool and easy! Ive learned this before in school.
  15. Profile photo of Nickel2
    Nickel2 Male 50-59
    5879 posts
    November 20, 2013 at 12:27 am
    The Scots are well known for being calculating...


  16. Profile photo of Essersmith
    Essersmith Male 18-29
    275 posts
    November 20, 2013 at 12:51 am
    @Nickel2

    553 * 352 = 194656

    I tried it the japanese way. Perhaps once you are very familiar with the system its fast. But it took me longer to sit and count and add than it took the way I was taught.
  17. Profile photo of Essersmith
    Essersmith Male 18-29
    275 posts
    November 20, 2013 at 12:54 am
    Crud, I miscalculated, I didnt count the blue lines!
  18. Profile photo of Essersmith
    Essersmith Male 18-29
    275 posts
    November 20, 2013 at 1:12 am
    Lets try again:

    996 * 693 = 690228
    Less than a minute to do by "old fashion" hand calculation. This is slow aswell I suppose.

    About 2 minutes with the japanese system.
    Id love to see a japanese person do this, I presume the drawing of the system becomes less needed once you get used to it.

  19. Profile photo of drawman61
    drawman61 Male 50-59
    7707 posts
    November 20, 2013 at 2:30 am
    So is someone going to explain?
    No one I always hated mathS.
  20. Profile photo of Essersmith
    Essersmith Male 18-29
    275 posts
    November 20, 2013 at 3:20 am
    @drawman

    They count the number of times lines cross eachother. They go left to right, counting diagonally. So 1, 5, 6. Means that top left the lines cross 1 time. middle diagonal they cross a total of 5 times and bottom right cross 6 times.

    The numbers represent digits and 1`s, 10`s, 100`s and so on. going from high to low. The 1 represent 100, 5 represent 50 and the 6 representy 6.

    If the lines add up to say 12. Then, given the lines location, it represents 12, 120, 1200 and/or so on.
    Try to apply it to the slightly larger calculation. It makes sense, in a japanese kind of way.
  21. Profile photo of Laran
    Laran Male 40-49
    467 posts
    November 20, 2013 at 5:34 am
    This is called Vedic maths.
    Its actually from India.as a kid I could use this method before I learned the western method.
    My teachers actually graded my work as an F once because even though my answers were correct, I could not show them my working out.
  22. Profile photo of patchouly
    patchouly Male 40-49
    4746 posts
    November 20, 2013 at 5:57 am
    Slow and crude. I think the way we do it is much more efficient.
  23. Profile photo of deyv87
    deyv87 Male 18-29
    302 posts
    November 20, 2013 at 7:16 am
    To be honest, this is good for teaching the concepts behind multiplication of multi-digit numbers in a way that naturally leads to polynomial multiplication. It`s just pointing out that the first one, 13*12, is equivalent to (10+3)*(10+2), then you distribute it to 10*10+10*3+10*2+3*2 which equals 156. Same for anything larger. 123*456 = (100+20+3)*(400*50*6)=(100*400 + 100*50 + 100*6 + 20*400 + 20*50 + 20*6 + 3*400 + 3*50 + 3*6)= 40000 + 5000 + 600 + 8000 + 1000 + 120 + 1200 + 150 + 18 = 56088. The concept expands to polynomial multiplication since everything so far has just been polynomial multiplication with single digit coefficients and with x=10. So if x=10, then (327*151) = (3x^2+2x+7)*(x^2+5x+1)= (3x^4 + 15x^3 + 3x^2 + 2x^3 + 10x^2 + 2x + 7x^2 + 35x + 7) = 3x^4+17x^3+20x^2+37x+7. Plugging 10 back in for x, 30000+17000+2000+370+7 = 49377.
  24. Profile photo of Essersmith
    Essersmith Male 18-29
    275 posts
    November 20, 2013 at 7:54 am
    @Deyv well put.
  25. Profile photo of Mikeoxsbiggg
    Mikeoxsbiggg Male 30-39
    1502 posts
    November 20, 2013 at 7:59 am
    My question is how does someone sit down and hammer this method out? Imagine the trial and error beforehand.
  26. Profile photo of drawman61
    drawman61 Male 50-59
    7707 posts
    November 20, 2013 at 8:37 am
    @essersmith- Ah, I see it now, thanks.
  27. Profile photo of Essersmith
    Essersmith Male 18-29
    275 posts
    November 20, 2013 at 9:26 am
    @Mikeoxdbiggg
    Imagine quantum physics or simple integral methods.
    I doubt I would come up with this by my self, but this appears quite "simple".
  28. Profile photo of YugureKage
    YugureKage Female 18-29
    1205 posts
    November 20, 2013 at 9:39 am
    the new way kids here are being taught to multiply is just freaking strange
  29. Profile photo of MikeyNiv
    MikeyNiv Male 18-29
    697 posts
    November 20, 2013 at 1:45 pm
    This is really old and not even that effective, simple long multiplication is easier
  30. Profile photo of Gerry1of1
    Gerry1of1 Male 50-59
    36213 posts
    November 20, 2013 at 5:34 pm

    I got stuck at `5`
  31. Profile photo of TJEx
    TJEx Male 30-39
    86 posts
    November 20, 2013 at 10:52 pm
    Common Core will just say that if you confuse the teacher enough and BS enough you can get 2+2=5 marked correct.

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