Find the unit digit of 7^105.
A1
B3
C7
D9
Explanation
Cyclicity of 7 is 4 (7, 9, 3, 1). 105 mod 4 = 1. Therefore, unit digit is 7^1 = 7.
Exam Relevance
- Topic: Number System
- Subtopic: Cyclicity & Unit Digit

No Comments