Correct Answer - Option 4 : 6
Given:
(764)25 – (277)21 + (263)46.
Concept used:
By using cyclicity rules.
Calculation:
(764)25 – (277)21 + (263)46
⇒ (764)6×4 + 1 – (277)4×5 + 1 + (263)4×10 + 2
⇒ 41 – 71 + 32
⇒ 4 – 7 + 9
⇒ 6
∴ The unit digit of the number (764)25 – (277)21 + (263)46 is 6.