I have seen this question but i could not find any answers.Let
A= a*b*c*d.... very huge multiplication
So what we can do take
log(base 10) of number
log(A) = log(a)+log(b)+log(c)..... log(A) = S (summation of logs)
From here onward how can i find the first digit. I came to know that
Fist digit = Number after decimals in S which is close to log of (1..9)
Can you explain how to do that ?