What is the remainder when 2^{1000000} is divided by 7?

  1. A. 1
  2. B. 2
  3. C. 4
  4. D. 6

Correct Answer: B. 2

Explanation

Using cyclicity, 2^3 = 8 \equiv 1 \pmod{7}. Since 1000000 = 3 \times 333333 + 1, we have 2^{1000000} = (2^3)^{333333} \times 2^1 \equiv 1^{333333} \times 2 \equiv 2 \pmod{7}.

Related questions on Arithmetic

Practice more CDS Elementary Mathematics questions