The number 2^1993 + 3 is a multiple of 5. What is the units digit of the quotient (2^1993 + 3)/5?
(2^1993 + 3)/5 mod 10^10==3829920359 - these are the last 10 digits of the quotient.
A similar problem is solved here: https://web2.0calc.com/questions/inverse-mod#r4
