Stage: 5 Challenge Level: 
What are the possible remainders when the $100^{th}$ power of an integer is divided by $125$?
Inequality/inequalities. Manipulating algebraic expressions/formulae. Modulus arithmetic. Mathematical reasoning & proof. alphas. epsilons. Summation of series. Index notation/Indices. Binomial Theorem. Stage 5 - Reviewed 2012.
Published May 2002.
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