Check Multiplication Sums Using Digital Root

In Previous post we learn about how to check addition and  subtraction using digital root.
Now a smarter way of checking multiplication sums.

REMEMBER

The digital root of a product is the product  of the digital roots

of the numbers being multiplied.

Lets understand by an example.

1. Multiply  two numbers 254 * 231

2. Digital root of 254 is2

3. Digital root of 231 is 6

4. Now Multiply 2*6 is 12. Further digital root of 12 is 3.

This implies that Digital root of  254 * 231  will also be 3. Let's verify.

5. Multiply 254 * 231 = 58674

6. Digital root of   58674  is 5+8+6+7+4= 30 again 3+0 = 3

Hence the digital root of the final answer is equal to the product  of the digital roots of 2 numbers.


Practise to master this art.   Enjoy maths..