Great method for multiplication

So I came across this really cool method for multiplication that I wanted to share. I am usually firmly against Common Core techniques and this did look like one at first. I am blown away by it though and cant deny its simple but effective methodology. It also inspires deeper thought when applying this to the real world. My kid is going to learning this today.

They say in the video that this method originates from Japan, and makes me wonder if its not a Kumon technique from their founder. www.kumon.com... (Great program for getting kids to be able to do calculus before high school and great general all round math after school program)

This technique is sometimes referred to as the Chinese method so I am not sure where exactly it comes from. Either way its awesome and worth adding to the mental tool box. Check it out.



Here is another great method: Gelosia Method of Multiplication.

a reply to: tadaman

I liked the first method, showed it off to a couple of associates who have younger kids, they immediately saw the use of it.

a reply to: tadaman

I enjoy practicing on a soroban. It is the most simplified abacus I can imagine and if you can visualize its physical relationships in your head, you can do calculations rapidly without needing to think about numbers at all really. The soroban allows you to decimalize your numbers, which is really amazing, and Japanese students who are expert at it can perform calculations in their head faster than modern computers.

Ty for posting. I don't want this to be a simple so I can find it again post.

I can't wait for my kids to get home to see if they like it! The hardest thing for me is that the methods they are learning don't make sense when you learned math "old school".

I refuse to believe I'm the only parent that just shows them the other way.

That is cool!

Just blew my 10 year Olds mind how easy it was to multiply big numbers (which scare him )!

I just thought I would post somethings the video doesnt mention. My kid picked up on them and tried to fry my brain. LOL It is common sense but for the sake of those of us trying to teach difficult children or even just kids that lose interest easily here are some gimmicks you can use to make them play along.

If you use a number with a zero like 20 or 100 just draw the lines you can and since zero doesnt get a line drawn for it, count the zeros and add those to the answer at the end.

Also in the video the guy makes circles and vertical loops for each section. You will probably be making diagonal loops in reality.

Ok if you use 3 or more digit numbers: Basically just make squares, and for each new digit add another section of square using the last line of the of the last square. Then flip the squares to make a diamond. Thats more for organizational issues and sanity.

Then tell them to make diamonds and look for triangles to determine the sections. If you are sloppy like me you lose track. The first and last section will only form triangles along either the top or bottom lines where they intersect on the crossed lines at the beginning or the end. Like left and right will be lonely sections. The middle sections like a diamond have top and bottom sets of triangles.

If you realize, it will always be the case that if your largest number has 3 digits you will have 4 sections of squares... 4 digits you will have 5 sections of squares...5 digits you will have 6 sections and so on. The video makes it look easy and it is, but teaching it to a smart ass will bring up these issues LOL Make them keep that in mind if they are too spacey to not start drawing a spider web or something in the process of teaching them....LOL

SO make squares as shown and tell them to turn the paper to see the diamond. Diamonds have left and right single triangles and in the middle you have up and down triangles.

If you skew it some and arent neat just tell them to go up and down from groups of triangles to determine the sections going from left to right and from bottom line to top line.

SO

The first section starts where the lines intersect on the bottom line and form a triangle. Then the next section will have an up and down set of triangles but will START on the top line and end on the bottom line. Then the next section will start on the top line and end on the bottom line until you get to the lonely section with just a top line triangle,...(remember you started with a lonely bottom line triangle for the first section.)

Its convoluted for something so easy, but if your kid is like mine you will understand. And remember to add those zeros!

Click thumb for an image of what I am talking about

I just thought I would throw this in here too. Its a popular method for long division that many will already know. Maybe not but here it is anyways.

Chunking: Using chunks of multiples to divide.




This is great for kids learning that find the traditional method confusing. Think of it this way, the sooner they master these things and can do them quickly with no errors, the better off they will be for calculus. That ability to do calculus means that math becomes an enhancement for their future career choices instead of a limiting factor to them for not "being good at math"....


This may be better, but I still think the traditional method of chunking is good. Thats how I learned it so I may be partial. You decide.


Oh and fractions...this is actually the way I learned it in school myself. Its the best way.

Frigging amazing thanks

Wicked. I just been trying out different equations, and am going to show my daughters teacher after school. My partner also taught me one to work and 1-10 multiplication using your two hands, but I can't remember it now and prob could explain it or draw a diagram, maybe one of yous fellas might know it. I get all panickey when some one asks my to do number stuff, I think I'm number dyslexic.
Happy counting everyone.