2014 UNM-PNM Statewide High School Mathematics Contest II Problems/Problem 5

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Problem

$5^n$ is written on the blackboard. The sum of its digits is calculated. Then the sum of the digits of the result is calculated and so on until we have a single digit. If $n = 2014$, what is this digit?

Solution

See also

2014 UNM-PNM Contest II (ProblemsAnswer KeyResources)
Preceded by
Problem 4
Followed by
Problem 6
1 2 3 4 5 6 7 8 9 10
All UNM-PNM Problems and Solutions