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guys how can i compute teh last digit of a number , resulting from tetration without computing the real number..

for example ...5||2 = 2^65536...how can i get the last digit of that number without computing it..teh last 8 digits for example ?

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deepinlife Wrote:guys how can i compute teh last digit of a number , resulting from tetration without computing the real number..

for example ...5||2 = 2^65536...how can i get the last digit of that number without computing it..teh last 8 digits for example ?

See

here.

Where do you guys get those questions? Is it a homework exercise or so?

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bo198214 Wrote:Where do you guys get those questions? Is it a homework exercise or so?

These questions are very common in contests, like the

Putnam Competition.

Andrew Robbins

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