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Bunuel
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Bunuel
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What is the most efficient way to find the prime divisors of 143? It is not obvious that 143 is divisible by 11 or 13. Any suggestions?
Good question, Lweston. It does help to have your squares memorized up to 15. You would then know, for instance, that \(11^2=121\), and there is a clearly discernible difference of 22--a multiple of 11--between 143 and 121. Or, starting with 13, you could subtract from \(13^2=169\). That is, \(169-143=26\), a multiple of 13.

A little work ahead of time can come up big on certain problems. That is my take on this one, anyway.

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I have edited the question and the solution by adding more details to enhance its clarity. I hope it is now easier to understand.
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I think this is a high-quality question and I agree with explanation.
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