Question

determinati ultima cifra a numerelor. ex 6

Answer 1

2017 = 4 × 504 + 1

Uc(2^2017) = Uc(2^1) = 2
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Uc(3^2017) = Uc(3^1) = 3
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Uc(5^2018) = 5

5 la orice putere, are intotdeauna ultima cifra 5
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Uc(7^2020) = Uc(7^4) = Uc(2401) = 1
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2021 = 4 × 505 + 1

Uc(8^2021) = Uc(8^1) = 8
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Uc(9^2022) = 1

2022 este nr par si se stie ca 9 la o putere para are ultima cifra intotdeauna 1 .

iar 9 la o putere impara are intotdeauna ultima cifra 9 .