2020 · Q11
If 17²⁰²⁰ is divided by 18, then what is the remainder?
Elementary MathematicsNumber System
- A1
- B2
- C16
- D17
Explanation
17 is congruent to -1 modulo 18, so 17^2020 = (-1)^2020 = 1. The remainder is 1 - option (A). Equivalently, 17^2 = 289 = 16*18+1, so every even power of 17 is 1 modulo 18.