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Fermat's little theorem and congruence equationsEdexcel A-Level Further Maths: Flashcards

What these 12 flashcards ask

  • State Fermat's little theorem.
  • Alternative form of Fermat's little theorem?
  • How do you reduce a^k\pmod p?
  • Least positive residue of 4^{20} modulo 7?
  • Remainder when 12^{50} is divided by 7?
  • When does ax\equiv b\pmod n have a solution?
  • How many solutions modulo n does it have?
  • What is the multiplicative inverse of a modulo n?
  • How do you find a multiplicative inverse?
  • Inverse of 17 modulo 40?
  • Solve 7x\equiv3\pmod{11}.
  • Solve a congruence when d=hcf(a,n)1 and d\mid b.

Exam questions on Fermat's little theorem and congruence equations

  1. Work modulo 77, which is prime.
    Find the remainder when 125012^{50} is divided by 77.2 marks
  2. Linear congruences of the form ax≡b(modn)ax\equiv b\pmod n are to be solved for integers xx.
    Solve 7x≡3(mod11)7x\equiv3\pmod{11}.2 marks
  3. Consider the numbers 1717 and 4040.
    Use the Euclidean algorithm to show that 1717 and 4040 are coprime.3 marks
See the full worksheet

Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).