Vedic Maths Article 1: Multiplying two digit nymbers by 11

Our god gets angry if we pray in a different way
May 9, 2018
Vedic mathematics article 2: subtraction of numbers from 10, 100, 1000, 10 000, etc.
May 9, 2018

Vedic Maths Article 1: Multiplying two digit nymbers by 11

Young boy writes math equations on chalkboard

Namaste everyone. Welcom to my Blog. In this blog I will be posting articles from my Vedic maths column within the Vishwa Shakti Magazine. You are free to go through my content, post comments and ask questions based on any of my articles. I hope these posts will be useful to you as it was to me. Have fun and remember that we can only become better at something if we keep practicing. 

Vedic Mathematics is an ancient Indian mathematical system which was recently re-discovered by the Vedas. By studying Vedic Mathematics with its creative and innovative methods, many students will find the subject of Mathematics more enjoyable. In the former subject, simpler methods are used to find solutions (sometimes allowing for mental calculations of answers).

If I had to ask you, what is 72 x 11, can you give me the solution within three seconds? For many people, this would be a task involving a calculator. By the time you find a calculator (or try working out the answer on your cellphone), you could have already solved this question by using Vedic Maths. In just a few seconds, you would surprise your friends with your amazing mathematical skill. In fact, the technique is simple enough for a Grade 4 student to understand.

In case you were wondering about the answer to the above question, it is 792. How did I get this answer using Vedic Maths? In the number 72, add the first digit (7) to the second digit (2). Answer? 9. You have just finished half of the technique of solving any two-digit number multiplied by 11. All you have to do now is create a “gap” in-between the two digits of the number you are multiplying by 11, and slot in your sum (in this case, it’s 9). Thus we can see that 72 x 11 = 792, as the 9 has been inserted in-between the 7 and 2. Simple, isn’t it?

Let’s try a more difficult problem. Try 38 x 11. We apply the same rule stating that you have to add the two digits (3 + 8) and sandwich the sum in-between the original number. So let’s try this: 3 + 8 = 11, so the answer must be 3118. WRONG! What needs to be realized is that there is only one-digit-space in between the 3 and 8, so the number 11 would have to be split up into a tens-digit and  a units-digit. Due to this limited space, the 1 from the tens digit must be added to the hundreds column, thus making it 3+1;1;8, which simplifies to 418.

Now you can see the simplicity of this method! The normal addition of two numbers can be used to determine the product of any two-digit number multiplied by 11, by simply placing the sum in-between the two numbers. Remember that if the sum of the two digits in the number is equal to two-digit-spaces, then add 1 to the hundreds column and sandwich the units digit in-between the original two numbers. This technique demonstrates the possibilities of using Vedic Mathematics. The only problem with this technique, however, is that it is limited to the 11 times table only.

EXAMPLES: 

21 x 11 = 2_1                      231

34 x 11= 3_4                       374

52 x 11= 5_2                       572

66 x 11= 6_6                       726

89 x 11= 8_9                       979

Rushern Chetty – Grade 12 Scholar