In this blog, I will explain a very easy method of multiplication by 11 which is indeed saves a lot of time.
Suppose we have to multiply 723 by 11. In this easier method of multiplication, we will achieve the result using only simple addition.
The trick is to add repeatedly from right to left. In this example, we would start by writing the units digit of our product as the units digit of 723. This means that the product ends with the digit three. Now, start from the right and move to the left by adding 3+2=5. Write that as the tens digit to your final product. Next add the following pair of numbers, 7+2=9, which in turn is the hundreds place of your final product. Assume that there is a zero before the 7 in the number 723, which makes your next pair, 7+0=7. Your final product should be 7953.
However, if the digits add up to be a number greater than 9, simply carry over to the next addition pair. For example: