Maths Olympiad Prep

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, 2007

Number theory Difficulty 3.0 AMC 10/12 Prove it Canada

A number is divisible by 8 if the number formed by its last 3 digits is divisible by 8. For example, the number 4738924847\,389\,248 is divisible by 8 because 248248 is divisible by 8. However, 4738928447\,389\,284 is not divisible by 8 because 284284 is not divisible by 8. If 9924661A6992\,466\,1A6 is divisible by 8, where AA represents one digit, what are the possible values of AA? Explain how you obtained your answer.

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