<p>What is the remainder when 2^400 is divided by ten?</p>
<p>Please tell me how you derived your answer quickly. Thanks</p>
<p>Where exactly did you find this question?</p>
<p>from the Pr manual, for the class</p>
<p>Try to make a rule out of the first powers:
Power of 2 <-> remainder after :10
1 <-> 2
2 <-> 4
3 <-> 8
4 <-> 6</p>
<p>The cycle repeats. Because 400/4 has no remainder, the cycle closes on 400. 2^400 leaves same remainder, as 2^4 => (6).</p>
<p>thanks a lot</p>