Linear equations

  • Seven Up
    problem

    Seven Up

    Age
    11 to 14
    Challenge level
    The number 27 is special because it is three times the sum of its digits 27 = 3 (2 + 7). Find some two digit numbers that are SEVEN times the sum of their digits (seven-up numbers)?
  • Small tomato seedlings in pink pots.
    problem

    Burning Down

    Age
    14 to 16
    Challenge level

    One night two candles were lit. Can you work out how long each candle was originally?

  • Small pepper seedlings in orange pots.
    problem

    Fractions of Fractions

    Age
    14 to 16
    Challenge level

    If you know that a fraction of X is the same as a different fraction of Y, can you work out X/Y?

  • Small pepper seedlings in orange pots.
    problem

    Big Fish

    Age
    14 to 16
    Challenge level

    Granny has taken up deep-sea fishing! Last week, she caught a fish so big that she had to cut it into three pieces in order to weigh it...

  • A Problem of time
    problem

    A Problem of Time

    Age
    14 to 16
    Challenge level

    Consider a watch face which has identical hands and identical marks for the hours. It is opposite to a mirror. When is the time as read direct and in the mirror exactly the same between 6 and 7?

  • Small pepper seedlings in orange pots.
    problem

    Months and Years

    Age
    14 to 16
    Challenge level

    The product of Mary's age at her last birthday and her age in complete months is 1800. How old is Mary?

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