Method for simple Maths

[abskebabs]

I've just seen this video, displaying a simple method for multiplication. What I liked about it was that it was very visual, and with a little perceptiveness, it is easy to see how it works too.

http://uk.youtube.com/watch?v=zr6eqxk038A&mode=related&search=

What do you think of it? Personally, I think it may be best for multiplication of numbers with small digits, as otherwise the method could become time consuming, and so overall I much prefer the Trachtenberg system which I am starting to get to grips with. I guess this method has some sort of attractiveness to me for some odd reason because it is visual, and perhaps exposes another way of thinking of the same thing when compared to other methods of multiplication.

[Pre4edgc]

That's pretty surprising... Never thought multiplication could be THAT easy... And if the numbers DO get pretty high, you could have art!

[CPL.Luke]

huh, I wonder why that works

[abskebabs]

If you're not sure about how it works, then think about what you're actually doing when multiplying. For example 2*2 is producing "2 lots of 2", so you can imagine the situation in terms of lines, I draw 2 parallel lines and I intersect them with 2 other parallel lines, producing 4 intersections, and thereby "doubling". You can have the situation in many other cases, using intersections in this case is just a handy way of visualising multiplication.

 

Now for the other aspect of the method, different sets of parallel lines are drawn for different powers of base 10, e.g. 1s, 10s, 100s etc. Each set intersects every other set at least once. Now you can interpret this and find the resultant intersections that make up different digits of your answer. For example if you are multiplying 2 2 digit Nos together, then to get the total No of the 10s digits you add together the No of line intersections produced at the point the 2 respective 10s and unit sets from each No intersect. If the sum is greater than 9, then you carry the 10s part of it into the hundreds part of your answer, similiar to how you would in other methods of multiplication.

 

Just remember you could split up this kind of multiplication in the following way: [math](10a+b)(10c+d)=100ac+(10ad+10bc)+bd[/math]

 

Also, referring to the comment about this looking like art... maybe some ppl might interpret it as that, but as a method I can see this becoming quite tiresome when large Nos and digits are involved, even though it is quicker than ordinary multiplication. I guess the painful, messy calculation could be thought of as a kind of art upon completion...

[cosine]

As an aside, I believe this method is part of a larger curriculum called Vedic mathematics, which claims to have roots in the Hindu Vedas, and has some following in Indian education.

[abskebabs]

Interesting, I was fully aware of vedic mathematics, but did not know this method had its roots in it. Between the trachtenberg system and vedic mathematics, I recently chose to pursue the former, and I think I am getting better at simple maths as a result, but the vedic maths may be worth looking over some time in the future too I guess.

[cjohnso0]

Neat,

 

It's definately not faster for numbers with larger digits. Try 9999 x 9999, not only do you need a big sheet of paper, it gets confusing real fast. It seems to take about the same amount of time (as standard multiplication) for smaller numbers though.