12x34=? (something i learnt today)

[monokekie]

[Over9000]

(Image removed from quote.)

Just use ur calc, or 10x34 + 2x34 = 340 + 68 = 408.
A squarish thing wont help u much.

[dcc]

I don't quite understand this square, but splitting up the multiplication as >9000 has done is the non-calculator method I would suggest (because we LOVE multiplying by 10).

[shinny]

It's exactly the same as doing (yes, cbf latex)

  34
x12
---
  68
340
---
408

but on a slant, so you don't need to add the extra 0 in the fourth line. There's a much better way of mentally doing any two digit multiplication which I'd come across once, but can't quite remember how to do it.

[/0]

There is a cross-multiplying method for 2-digit numbers. You multiply the two numbers in the unit's column and put this as the unit's digit. Then you cross-multiply as shown in the example, putting this in the ten's, and finally multiply the two numbers in the ten's column and put this as the hundred's. Any remainders are carried over.



The is gotten by

The is gotten by cross-multiplying:

The is gotten by

Personally I always do it this way, except when I spot something nice like over9000 seems to always do

[Johnle]

(Image removed from quote.)

I dont understand y drawing squares

[Visionz]

 34
X12
4x2 = 8
30+10 = 40
408(34x12) O_O

 27
x11
7x1 = 7
20+10 = 30
307 - 10 = 297 (27x11)

 55
x17
5x7= 35
5+5-1 = 9
935 (55x17)

kthxbai

[physics]

i don't get the square

[brightsky]

i don't get the square

The question is 12 x 34.

For 34, you split it into 3 and 4 and draw 3 lines and 4 lines respectively as two opposite sides of the square.

For 12, you do the same thing, splitting 1 and 2.

As you can see in the picture, the numbers written on each corner correspond to the number of blue lines multiplied by the number of pink lines intersecting at the corner.

So arithmetically, the four numbers would be represented as:







Tell me if I've got this wrong. :p

[the.watchman]

Yeah it's right, but I'm not sure how useful it is.
It's just a visualisation tool really...

[brightsky]

Yeah it's right, but I'm not sure how useful it is.
It's just a visualisation tool really...

Yeah, another way of expressing long division. But instead of numbers, you do it with lines and colours!

[v3n0m]

I dont know why but i prefer long division better then short one. I gues that's how i grew up.