Let’s recall how we used to multiply by 11 in our younger days.
5 4 x 1 1
5 4
5 4 x
5 9 4
However, there’s an easier way to do this. Check this
5 4 x 1 1
5 (5+4) 4
5 9 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 (6+7) 7
6 13 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 13 7
(6+1) 3 7
7 3 7
You can apply this trick to more than two digit number. Check out this.
3 2 2 4 x 1 1
3 (3+2) (2+2) (2+4) 4
3 5 4 6 4
I hope you got the point. If not, feel free to comment below. Till we show you another trick, keep practicing. Happy calculating :).
