I will illustrate multiplication of two numbers using a sutra from Vedic Math called “All from Nine and the last from Ten” (Sanskrit - Nikhilam Navatashcaramam Dashatah). I will choose a special case to illustrate this. But, this can be expanded to any multiplication. The sutra basically means start from the left most digit and begin subtracting ‘9’ from each of the digits; but subtract ‘10’ from the last digit.
Find the complete tricks in the attached PDFs.