Is the Calculation of the Last Digit of 10^1000 Mod 8 Correct?

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SUMMARY

The calculation of the last digit of 10^1000 modulo 8 is confirmed to be 0. The discussion outlines the steps taken, starting with the equivalence 10^2 ≡ 4 (mod 8) and progressing to (10^2)^500 ≡ 4^500 (mod 8). It further establishes that 4^2 ≡ 0 (mod 8), leading to the conclusion that (4^2)^250 ≡ 0 (mod 8). Therefore, the last digit of 10^1000 mod 8 is definitively 0.

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Homework Statement


What is the last digit of 101000 (mod 8)

Homework Equations





The Attempt at a Solution



10^2\equiv4 (mod 8)

(10^2)^500\equiv 4^500 (mod 8)

4^2=0 (mod 8)

(4^2)^250\equiv0^250\equiv0 (mod 8)

Thus, the last digit is 0.

Are these steps mathematically legal?
 
Last edited:
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ya, what you have done is absolutely fine
 

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