Questions On GCD(Euclid’s Algorithm), Modular properties, Fermat’s little theorem, modular exponentiation

• Codechef FLOW016 - GCD and LCM

• Codechef GCDQ - GCD Queries

• Codechef GCD2 - GCD2

• Spoj MARBLES - Marbles

• Spoj LCMSUM - LCM Sum

• Hackerearth - Shantam and Richness

• Hackerearth - Panda and Chain Reaction

• Hackerearth - Selection of Cities

• Hackerearth - Calculate the Power

• Hackerearth - Unlock the Door

• Codeforces - Beautiful Numbers

• Codeforces - Dima and Sequence

• Codeforces - Nastya and a Wardrobe

• Codeforces - Max History

Some Reading material

• Basics of Number Theory

• Proof of Euclid’s Algorithm

• Proofs of Fermat’s little theorem