Indices

  • eNRICHing experience
    problem

    eNRICHing experience

    Age
    14 to 16
    Challenge level
    filled star empty star empty star

    Find the five distinct digits N, R, I, C and H in the following nomogram

  • Power Quady
    problem

    Power quady

    Age
    16 to 18
    Challenge level
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    Find all real solutions of the equation (x^2-7x+11)^(x^2-11x+30) = 1.
  • Multiplication Magic
    problem

    Multiplication magic

    Age
    14 to 16
    Challenge level
    filled star empty star empty star
    Given any 3 digit number you can use the given digits and name another number which is divisible by 37 (e.g. given 628 you say 628371 is divisible by 37 because you know that 6+3 = 2+7 = 8+1 = 9). The question asks you to explain the trick.
  • Elevens
    problem

    Elevens

    Age
    16 to 18
    Challenge level
    filled star empty star empty star
    Add powers of 3 and powers of 7 and get multiples of 11.
  • More Mods
    problem

    More mods

    Age
    14 to 16
    Challenge level
    filled star filled star empty star
    What is the units digit for the number 123^(456) ?
  • Growing
    problem

    Growing

    Age
    16 to 18
    Challenge level
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    Which is larger: (a) 1.000001^{1000000} or 2? (b) 100^{300} or 300! (i.e.factorial 300)
  • Power Up
    problem

    Power up

    Age
    16 to 18
    Challenge level
    filled star filled star empty star
    Show without recourse to any calculating aid that 7^{1/2} + 7^{1/3} + 7^{1/4} < 7 and 4^{1/2} + 4^{1/3} + 4^{1/4} > 4 . Sketch the graph of f(x) = x^{1/2} + x^{1/3} + x^{1/4} -x
  • Remainder Hunt
    problem

    Remainder hunt

    Age
    16 to 18
    Challenge level
    filled star filled star empty star
    What are the possible remainders when the 100-th power of an integer is divided by 125?
  • Thirty Six Exactly
    problem

    Thirty six exactly

    Age
    11 to 14
    Challenge level
    filled star filled star empty star
    The number 12 = 2^2 × 3 has 6 factors. What is the smallest natural number with exactly 36 factors?
  • Even So
    problem

    Even so

    Age
    11 to 14
    Challenge level
    filled star filled star empty star
    Find some triples of whole numbers a, b and c such that a^2 + b^2 + c^2 is a multiple of 4. Is it necessarily the case that a, b and c must all be even? If so, can you explain why?