2019 · Q19
What is the unit place digit in the expansion of 7⁷³?
Elementary MathematicsNumber System
- A1
- B3
- C7
- D9
Explanation
Powers of 7 end in 7, 9, 3, 1 cyclically (7^1, 7^2, 7^3, 7^4). 73 = 4×18 + 1, so 7^73 ends like 7^1, i.e. in 7.
What is the unit place digit in the expansion of 7⁷³?
Explanation
Powers of 7 end in 7, 9, 3, 1 cyclically (7^1, 7^2, 7^3, 7^4). 73 = 4×18 + 1, so 7^73 ends like 7^1, i.e. in 7.