Let’s recall how we used to multiply by 11 in our younger days.
5 4 x 1 1
5 Â 4
5 Â 4 Â x
5 Â 9 Â 4
However, there’s an easier way to do this. Check this
5  4  x  1  1
5 Â (5+4) Â 4
5 Â Â 9 Â Â 4
[note style=”” bg=”” border=”” bordercolor=”{{bordercolor}}” color=””] Whenever you multiply an x-digit number by 11, you will always get x+1 digit answer. [/note]
What happened there?
- First digit of 54 became the first digit of answer 594
- Last digit of 54 became the last digit of answer 594
- Middle digit is the sum of surrounding digits 5+4
Lets try our hands on more complex problem.
6 7 x 1 1
6 Â (6+7) Â 7
6 Â 13 Â 7?
Remember, the note above, it can be only three digit long. So what happened here? Yes, you got it right, you need to carry “1” of “13” over 6 like this:
6  7  x  1 1
6 Â Â 13 Â Â 7
(6+1) Â 3 Â 7
7 Â Â 3 Â Â 7
 You can apply this trick to more than two digit number. Check out this.
3 2 2 4 x 1 1
3 Â (3+2) Â (2+2) Â (2+4) Â 4
3 Â 5 Â 4 Â 6 Â 4
I hope you got the point. If not, feel free to comment below. Till we show you another trick, keep practicing. Happy calculating :).
