Explaining, convincing and proving

  • OK! Now prove it
    problem

    Ok! Now Prove It

    Age
    16 to 18
    Challenge level
    2 out of 3

    Make a conjecture about the sum of the squares of the odd positive integers. Can you prove it?

  • Exhaustion
    problem

    Exhaustion

    Age
    16 to 18
    Challenge level
    2 out of 3

    Find the positive integer solutions of the equation (1+1/a)(1+1/b)(1+1/c) = 2

  • Binary Squares
    problem

    Binary Squares

    Age
    16 to 18
    Challenge level
    2 out of 3

    If a number N is expressed in binary by using only 'ones,' what can you say about its square (in binary)?

  • Basic Rhythms
    problem

    Basic Rhythms

    Age
    16 to 18
    Challenge level
    2 out of 3

    Explore a number pattern which has the same symmetries in different bases.

  • Little and Large
    problem

    Little and Large

    Age
    16 to 18
    Challenge level
    2 out of 3

    A point moves around inside a rectangle. What are the least and the greatest values of the sum of the squares of the distances from the vertices?

  • Square Pair Circles
    problem

    Square Pair Circles

    Age
    16 to 18
    Challenge level
    2 out of 3

    Investigate the number of points with integer coordinates on circles with centres at the origin for which the square of the radius is a power of 5.

  • Polite Numbers
    problem

    Polite Numbers

    Age
    16 to 18
    Challenge level
    2 out of 3

    A polite number can be written as the sum of two or more consecutive positive integers, for example 8+9+10=27 is a polite number. Can you find some more polite, and impolite, numbers?

  • Generally Geometric
    problem

    Generally Geometric

    Age
    16 to 18
    Challenge level
    2 out of 3

    Generalise the sum of a GP by using derivatives to make the coefficients into powers of the natural numbers.

  • Cube Net
    problem

    Cube Net

    Age
    16 to 18
    Challenge level
    2 out of 3

    How many tours visit each vertex of a cube once and only once? How many return to the starting point?

  • Can it be?
    problem

    Can It Be?

    Age
    16 to 18
    Challenge level
    2 out of 3

    When if ever do you get the right answer if you add two fractions by adding the numerators and adding the denominators?