Number theory

  • Sums of Squares and Sums of Cubes
    article

    Sums of Squares and Sums of Cubes

    An account of methods for finding whether or not a number can be written as the sum of two or more squares or as the sum of two or more cubes.
  • Powerful properties
    article

    Powerful Properties

    Yatir from Israel wrote this article on numbers that can be written as $ 2^n-n $ where n is a positive integer.
  • Got \It Article
    article

    Got It Article

    This article gives you a few ideas for understanding the Got It! game and how you might find a winning strategy.
  • Placeholder: several colourful numbers
    article

    Binomial Coefficients

    An introduction to the binomial coefficient, and exploration of some of the formulae it satisfies.

  • Euler's Squares
    problem

    Euler's Squares

    Age
    14 to 16
    Challenge level
    filled star empty star empty star
    Euler found four whole numbers such that the sum of any two of the numbers is a perfect square...
  • There's a limit
    problem
    Favourite

    There's a Limit

    Age
    14 to 18
    Challenge level
    filled star empty star empty star
    Explore the continued fraction: 2+3/(2+3/(2+3/2+...)) What do you notice when successive terms are taken? What happens to the terms if the fraction goes on indefinitely?