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Thursday, February 26, 2004 - 04:01 PM
Here's how you can directly write down the answer to any number multiplied by 11. Take for example the number 51236 X 11.
First, write down the number with a zero in front of it.
051236
The zero is necessary so that the rules are simpler.
Draw a line under the number.
Bear with me on this one. It is simple if you work through it slowly. To do this, all you have to do this is "Add the neighbor". Look at the 6 in the "units" position of the number. Since there is no number to the right of it, you can't add to its "neighbor" so just write down 6 below the 6 in the units col.
For the "tens" place, add the 3 to the its "neighbor" (the 6). Write the answer: 9 below the 3.
For the "hundreds" place, add the 2 to the its "neighbor" (the 3). Write the answer: 5 below the 2.
For the "thousands" place, add the 1 to the its "neighbor" (the 2). Write the answer: 3 below the 1.
For the "ten-thousands" place, add the 5 to the its "neighbor" (the 1). Write the answer: 6 below the 5.
For the "hundred-thousands" place, add the 0 to the its "neighbor" (the 5). Write the answer: 5 below the 0.
That's it ... 11 X 051236 = 563596
Practice it on paper first!
First, write down the number with a zero in front of it.
051236
The zero is necessary so that the rules are simpler.
Draw a line under the number.
Bear with me on this one. It is simple if you work through it slowly. To do this, all you have to do this is "Add the neighbor". Look at the 6 in the "units" position of the number. Since there is no number to the right of it, you can't add to its "neighbor" so just write down 6 below the 6 in the units col.
For the "tens" place, add the 3 to the its "neighbor" (the 6). Write the answer: 9 below the 3.
For the "hundreds" place, add the 2 to the its "neighbor" (the 3). Write the answer: 5 below the 2.
For the "thousands" place, add the 1 to the its "neighbor" (the 2). Write the answer: 3 below the 1.
For the "ten-thousands" place, add the 5 to the its "neighbor" (the 1). Write the answer: 6 below the 5.
For the "hundred-thousands" place, add the 0 to the its "neighbor" (the 5). Write the answer: 5 below the 0.
That's it ... 11 X 051236 = 563596
Practice it on paper first!
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Comments
51236 x 11
___________________
51236
+ 512360
----------------------------
= 563596
.....51236 x 11
__________________
.............51236
+........512360
----------------------------
=....... 563596
Let us seperate this number into two parts using comma(X,Y).
Now we start from right hand side.
* Write down Y
* Write down X+Y ,(keep the carry)
* Write down X+the carry
* Now write down (X + Carry),(X + Y), Y
Ex: Suppose that you want to multiply 51236 by 11
5123,6
First step
6
Second step
5123+6=5129 .
We write down 9 and take the carry as 512.
Third step
5123+512= 5635
Now the result is 5635,9,6.
You can multiply any amount of numbers with this trick.
Such as 6x11: 06x11=66 you simply apply the same principle, as you would with a 3
digit.
51236 x 10 = 512360 (shift the decimal point)
add : 512360 + 51236 = 563,596 QED!
Good point. (now why didn't I think of that in my homework?)
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