Product of 64 digit numbers using Karatsuba algorithm

Question

How to use Karatsuba algorithm to calculate product of two 64 digit numbers such that only single digit numbers take part in multiplication ?

Answer 1

I think you posted this after going through Tim Roughgarden's course. What he actually meant was that you should multiply only a single digit to another single digit at a time, rather than use the computer to multiply multiple digits for you. In other words, multiply as if a human does it.