its really not that cool, when you cross 2 lines with three lines you get 6 dots, and so on, he`s still doing each individual step but he`s just able to visualize it. it does take care of the values of each digit nicely, though.

Clever trick. Shinu, this is why it works: The spaced out lines correspond to ones, tens, hundreds, etc., just like the numbers in the decimal system (321=3 hundreds, 2 tens, 1 one--same for the 3,2,1 lines). There are at most two sets of each type of line, one for each number. That makes it possible to do the multiplication graphically: e.g 3x2 lines will intersect each other 6 times--you can see that. Where the lines intersect it`s like multiplying one by the other: e.g., if the ten line intersects a hundred line, you`re counting thousands. So the intersection of 3 hundreds and 2 tens, or 2 hundreds and 3 tens gets you 6 thousands. Since the lines are drawn in order, which place is which is also in order: e.g. at the bottom right, you are multiplying ones by ones, so you are counting ones. If you go one up or one to the left, you are multiplying ones by tens, so you are counting tens. Basically, every step up or to the left, moves the decimal place one to the right. That is wh

*continuing* That is why the diagonal lines match up the decimal places: imagine you start drawing the diagonal line from the top. You go down one and to the left one: going down reduces the place, but going to the left increases the place, so together they cancel out, and you are dealing with the same decimal place. (You can start from the bottom and go up and to the right--same thing). At the end, he carries whatever digits he needs to. It could get more complicated than he made it, with multiple carries, but that works the same as carrying in the standard way of doing these things. This is really the same thing as doing the multiplication the regular way (except you don`t need a multiplication table), so it does work for everything, 72tour. The only thing you have to add to take care of all the cases, is that he didn`t show how to write a zero. Suppose we make zero a dotted line, and don`t count intersections with dotted lines. Then it works for everything.

neat trick, just did 27 x 156 and got 4212 using lines, checked it with a calc and it was right. so then i did it long hand and found that to be alot quicker than the lines

thats pretty cool, but its like taking the scenic route when going somewhere, you know it takes longer but you want to try something different and it will increase your driving skills

Man, some of you guys just completely missed the point. Of course a calculator is better. This is not supposed to be the solution for failure in math. It`s supposed to be a cool trick. And it is. And YouG, thanks for the zero tip, was battling it that one.

So they are accepting math links? Then why not the Ten Commandments of Math I submitted a bit ago? Hum.

I suppose this method would help the visual learners, but I`m a math tutor at my local college and wouldn`t recommend this trick to anyone. It`s time consuming and requires more space on the paper. Oh, and some of you may be forgetting that in lower level math classes, calculators are not permitted.

^^lol tallun.if i was in school still or studying a college course that required the use of maths, i`d do it too.was thinking the same thing while watching it and was like "wonder what the teacher woulda done if i starting doing that all over my papers?"

There are loads of easier ways to do this. Longhand for starters. My year 5 teacher taught me a cool way which was in escence long division, but did in little steps and add it up all in your head. Which is why i can do 1283*134 mentally in 2 minutes when i dont have stuff to write on! lol

That`s the most useless thing I`ve ever seen. How is that any faster than doing it the old fashioned way? Not only that, who in their right mind does math without a calculator these days anyway?

it might look easy for 123 x 321, but imagine doing it with 948 x 769 or for that mather even 49 x 97 would take ages, having 81 intersections at one place, 63 at another, then 36 and finally 28. A lot of counting then.

Calculators are the worst thing to ever happen to math education.

Seriously. The best thing I ever did for getting good at math was lose my calculator early on in pre-calculus and not tell my parents.

And the lines would get faster in a hurry if you drew them faster. Too bad that long division is faster unless you are slow at multiplying by 7, 8, or 9, in which case you have more lines to draw.

Best part I can see about this is that it works with other base systems - suppose you want to multiply 6`b011101 by 6`b111001. Or 8`h1A by 8`h06. Could help.

Yeah, I mean, this trick is the COOLEST. I mean, yeah, we can all use calcualters, but what if you don`t have one? What if you can`t use one cause you`re taking a test? This trick would be so easy. ANd I like what dracokain said about the showing the work thing lol. Next time my teacher asks me to show my work I`m doing that lol

Manticore, I don`t know what you`re talking about this working with other base systems. This is exactly the same as multiplying with digits using pencil and paper. That also works with other base systems, but you have to remember that 3*7=16, (e.g.) instead of 21, and so forth. You have to remember that using this system also, so I don`t see how it helps at all.

I`d use that if I could remember it, I`m not the brightest at maths lol I use the box method anyway but then it takes ages to add them all up at the end.

That`s confusing! I tried it and I don`t get it. Maybe I`ll send it to my math teacher... nah. I think that person is from France. THey write their nines like a lower case English "G".

- Pretty cool trick.
The spaced out lines correspond to ones, tens, hundreds, etc., just like the numbers in the decimal system (321=3 hundreds, 2 tens, 1 one--same for the 3,2,1 lines). There are at most two sets of each type of line, one for each number. That makes it possible to do the multiplication graphically: e.g 3x2 lines will intersect each other 6 times--you can see that. Where the lines intersect it`s like multiplying one by the other: e.g., if the ten line intersects a hundred line, you`re counting thousands. So the intersection of 3 hundreds and 2 tens, or 2 hundreds and 3 tens gets you 6 thousands.

Since the lines are drawn in order, which place is which is also in order: e.g. at the bottom right, you are multiplying ones by ones, so you are counting ones. If you go one up or one to the left, you are multiplying ones by tens, so you are counting tens. Basically, every step up or to the left, moves the decimal place one to the right. That is wh

At the end, he carries whatever digits he needs to. It could get more complicated than he made it, with multiple carries, but that works the same as carrying in the standard way of doing these things.

This is really the same thing as doing the multiplication the regular way (except you don`t need a multiplication table), so it does work for everything, 72tour. The only thing you have to add to take care of all the cases, is that he didn`t show how to write a zero. Suppose we make zero a dotted line, and don`t count intersections with dotted lines. Then it works for everything.

my brainnnnn

me = nerd... i know...

I suppose this method would help the visual learners, but I`m a math tutor at my local college and wouldn`t recommend this trick to anyone. It`s time consuming and requires more space on the paper. Oh, and some of you may be forgetting that in lower level math classes, calculators are not permitted.

WOW this is amazing.

but it is cool in theory. i dont think i`ll ever use it tho.

My year 5 teacher taught me a cool way which was in escence long division, but did in little steps and add it up all in your head. Which is why i can do 1283*134 mentally in 2 minutes when i dont have stuff to write on! lol

/One...two...TWO boobies! Ah ah ah!!!

these lines sure would solve that problem

this is quite a good method if your bored and have time, its not faster but it would be fun to see what the teacher did when they saw this

But what if there wasa 9 hmmm?

I`d rather use a calculator

I`m not kidding.

I imagine it has some practical application, though. Might be a fun project.

Normally I just strain to figure it out until I break down and do that damned lattice method of multiplication

Seriously. The best thing I ever did for getting good at math was lose my calculator early on in pre-calculus and not tell my parents.

And the lines would get faster in a hurry if you drew them faster. Too bad that long division is faster unless you are slow at multiplying by 7, 8, or 9, in which case you have more lines to draw.

Best part I can see about this is that it works with other base systems - suppose you want to multiply 6`b011101 by 6`b111001. Or 8`h1A by 8`h06. Could help.

When my dad wakes up, I`m showing it to him. He`ll enjoy it. Silly little math freak.

Calculators pwn.

I use the box method anyway but then it takes ages to add them all up at the end.