Tricks multiplication 11

Maybe multiplication 1 x 11 until 9 x 11 you have it .

So it is easy , an example:

2 x 11 = 22

7 x 11 = 77

9 x 11 = 99

it is easy , but what if multiplication x 11 10 to 20 x 11 ?

How: 12 x 11 blackboard figures that will be multiplied 11 but please evacuate diameter !

1 _ 2 ( watch .In between 1 and 2 no room empty )

Mean ( _ ) is a blank between 1 and 2 .So if talk in the book , substitutes ( _ ) with spaces / hollow place 

And try the number of right second the number ( 1 + 2 ).

The results must be 3 right?

And put the number 3 between the two the number.Then it would be be like this :

Before = 1 _ 2

after = 132

but if multiplication 19 x 11 how to ?

How:

the contents of right a hollow place in between 1 and 9 ( 1 _ 9 ).

Then count 1 + 9.

The results must be 10 right?But answer not the result of 19 x 11 = 1109!

But how this :

Wrote before paper scrawl the 10.

And input the finally ( 0 ) it would be like this: 109.

But what about the numbers 1 his?How add the end of 19 ( 1 to his the numbers 1 his ( remainder ).

1 plus or minus one of the results 2 right?Well, now we switch last digits of 109 to 2 and the result being like this:

209.Try count by means of composing.The results must be 209.Easy right.