Library / /347 of 475

, 1999

Number theory Difficulty 2.0 Junior Find the answer Canada

The units (ones) digit in the product $(5+1)\left(5^3+1\right)\left(5^6+1\right)\left(5^{12}+1\right)$ is

(A) $6$ (B) $5$ (C) $2$ (D) $1$ (E) $0$

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Source: CEMC, University of Waterloo, licensed CC-BY-NC-4.0. Statement reproduced verbatim; metadata (topic, difficulty) added by this project. Solutions are the publisher's, linked not copied.