Day of the Week Puzzle: Solving with Modular (Clock) Arithmetic

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To solve the day of the week puzzle using modular arithmetic, the key is recognizing that the week repeats every seven days. The problem involves calculating 4^1000 days from a Sunday. Observations reveal a pattern in the remainders when powers of 4 are divided by 7: 4^1 gives a remainder of 4, 4^2 gives 2, 4^3 gives 1, and then it repeats. Since 1000 mod 3 equals 1, it follows that 4^1000 has the same remainder as 4^1, which is 4. Therefore, 4^1000 days from Sunday lands on Thursday.
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I have this question and you need to use Modular (Clock) Arithmetic to solve it. If there is any work I need to know that. If you don't know the answer, is there anyway you can just tell me the process of how to do it? Thank you very, very much! Here is the problem:

What day of the week will 4^1000 days from a Sunday?
 
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Have you considered that the week always repeats itself after seven days. Seven days after Sunday it's Sunday again, also after 7000000000 days. Consequently 700000000000000002 days from a Sunday it will be Tuesday. Would that help?
 
Well after looking at this, I noticed a pattern. When you square 4 the first time, the remainder of that number divided by 7 is 2. when you cube 4 the remainder is 1. When you put it to the 4th the remainder is 4, then this pattern repeats. So then since it is to the 1000, it would be 4 days after sunday.
 
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Thank you very, very much for your help! :smile:
 
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