Step 5: Vedic Multiplication Examples: 2-Digit by 2-Digit
Example 1: 42*21
1. Multiply the 2 highest digits (4 and 2), resulting in an 8.
2. For the next higher digit, cross multiply 4*1 (4) and 2*2 (4), and add together, producing the middle digit of 8.
3. For the lowest digit, multiply the 2 lowest digits (1*2) together, resulting in a 2.
4. Put all of the digits together to produce your answer (882)
A quick check on the calculator indicates our answer is indeed correct.
One thing that can and should be noted here is that the order in which you go through for the vedic process does not actually matter. So, we can similarly start with the lowest digit and work our way up to the highest digit.
Example 2: 67*23 (Starting with the lowest digit and working our way left)
1. Lowest Digit: Multiply the 2 lowest digits together (7*3), to get 21. Only one digit can be kept per place, so write a 1 and carry a 2 over to the next position.
2. Now, move over by 1 position on top, (3 will be multiplied by 6 now) and cross multiply pairs, decrementing the position on top while incrementing the position on the bottom. That is to say, multiply 3*6 (18) and 2*7 (14) and add them together (32). Write a 2, carry a 3 to the next position.
3. At this point, we have reached the end of the number, and thus incrementing the position on top is not possible. Thus, we simply increment the position on the bottom (2 will be multiplied by 6) and no cross multiplication will occur (as incrementing the bottom digit is not possible, we have reached the end of the number). So, 2*6 will be 12, so write a 2 and carry a 1.
4. Now that the multiplication has been completed, we have 2 numbers. The one on top is all of ones digits from the multiplications, and the one on the bottom is all of the carries that occurred. So, simply add these 2 numbers (221 and 1320) together, resulting in the answer (1541).
In the following steps, we will perform examples to expand the idea to higher orders of digits.