Japanese Multiplication - Using Lines

How Japanese kids learn to multiply in elementary school! 😯

[jtal]

you need an example where the dots add up to over 10, and how you carry over, e.g., 13, carry over the 10 to make the number in front go up by 1, and hold the 3 as the next digit.

[VerirrterWaschbaer]

For someone who has big trouble with multiplication, this helps immensely

I have no problem with division, addition or subtraction
But multiplication is really hard for me

I'd rather do this than any other method I know of

[koniel]

This is literally 10x easier than the way my teacher taught me

[lsupremacy]

ive learned more in this video then ive learned in my whole life.

[anonymous-mjwb]

Hahah screw the anerican way our teachers taught us!! Ima do it this way from now on🤣🤣 it is soooo easy.

[wizzerdddddddddd]

This is basically the same as the area model of multiplication where you split the numbers into four areas and add them up to get your answer. For example, 31x32 = (30+1)x(30+2) = 30x30 + 30x2 + 1x30 + 1x2. This is illustrated more clearly when you realize that each section represents the digit's place value, e.g. (3x3) (x100) + (3x2+1x3) (x10) + 1x2 (x1).

Btw, for those wondering what to do when you have to carry a number using this line method here's an example:
34x47
1) Start with the lower right hand corner and add the dots, you should get 28 (because 7x4=28). 8 is the one's digit in our answer, and we "carry" the 2 in 28 over to the next section.
2) Add the dots of the upper right and lower left, you should get 37 (because 7x3 + 4x4 = 21+16 = 37). Now add the "carry" from the last section which was 2: 37+2 = 39. 9 is the next digit in our answer. (So far we have 98 as the answer). We again "carry" the 3 from 39 to the next section.
3) Add the dots in the upper left, you should get 12 (because 4x3 = 12). Now add the "carry" from the last section which was 3: 12+3 = 15. So 5 is our next digit and we "carry" the 1. (so far we have 598)
4) There is no next section, so we can say there are 0 dots. Add the carry from the last section which was 1 and we get our last digit: 1. So our final answer is 1598.

[IAteMyLeftKindeyOnThursday]

Why did I learn common core when I could've had THIS??

[xxnavyboyxx]

How do you choose the arc sections correctly?

[philipcatuogno]

It's not about is it "faster, cooler, does it work if the product is over 10, "etc. It's simply showing kids that there is always more than one way to solve a problem. Kids don't need to be taught "The Way". They need to experiment and challenge themselves to try new things.

[milaskuse]

This is amazing! I am surprised for how easy this is. It makes math easy, thanks to this video!😁

[jewellmcgarrett]

What if you get double digits? I need help with 53*18. I get the numbers (from left to right) 5, 43, 24

[johnschultz]

It's rather "interesting" that all of the numbers being multiplied together here are small integers in each position whose products have no carry over to higher positions. Try 987 x 98 using this method. Have fun! I hope you like drawing lots of lines, counting lots of dots, and doing manual carry overs regardless!

[think]

My brain's way of instinctually tackling the 32 x 31 problem was this:
32 * 32 - 32 is the same, and easier.
But 32 is just 2^5 as all programmers know by heart. Also, there are two of them, and 5+5 = 10.
So now, it's 2^10 - 32.
All programmers also know well that 2^10 = 1024.
So finally, it's 1024 - 32 = 1000 - 8 = 992

[suyang]

This is immensely helpful if you can visualize the sticks in your head and count that way. After watching this video, I tried 22×13 and got 283 from simply counting the dots in my head. Obviously, if the number is very large, I cannot keep track of the visual; but for double digit multiplications I think this is really good.

[KAPL]

I tried 31*32
301*32 etc
But what about large digit number like
789*78 ?

[kerensabirch]

Not a good demonstration as it only deals with easy low digit numbers up to 3. What if the numbers are larger e.g. 68x49?

[Neyobe]

This seems great for kindergarteners and elementary schoolers, but as you need to do harder work and more of it, drawing a diagram takes way too much room. I would rather to the stacking method, but that’s just me

[blueprincess]

Great now I can use this for college math!

[nicole-lsjb]

🤯 That is the coolest thing I have ever seen.

[Cracktune]

I love this, more ways to tackle the same problem