Q1: What is the unit digit in {(6374)¹⁷⁹³ x (625)³¹⁷ x (341⁴⁹¹)}?

ANS:A - 0 

Unit digit in (6374)¹⁷⁹³ = Unit digit in (4)¹⁷⁹³     = Unit digit in [(4²)⁸⁹⁶ x 4]     = Unit digit in (6 x 4) = 4 Unit digit in (625)³¹⁷ = Unit digit in (5)³¹⁷ = 5 Unit digit in (341)⁴⁹¹ = Unit digit in (1)⁴⁹¹ = 1 Required digit = Unit digit in (4 x 5 x 1) = 0.