Addition and subtraction

  • Special 24
    problem

    Special 24

    Age
    7 to 11
    Challenge level
    Find another number that is one short of a square number and when you double it and add 1, the result is also a square number.
  • Zargon Glasses
    problem

    Zargon Glasses

    Age
    7 to 11
    Challenge level
    Zumf makes spectacles for the residents of the planet Zargon, who have either 3 eyes or 4 eyes. How many lenses will Zumf need to make all the different orders for 9 families?
  • Magic Circles
    problem

    Magic Circles

    Age
    7 to 11
    Challenge level
    Put the numbers 1, 2, 3, 4, 5, 6 into the squares so that the numbers on each circle add up to the same amount. Can you find the rule for giving another set of six numbers?
  • Arranging the Tables
    problem

    Arranging the Tables

    Age
    7 to 11
    Challenge level

    There are 44 people coming to a dinner party. There are 15 square tables that seat 4 people. Find a way to seat the 44 people using all 15 tables, with no empty places.

  • Number Juggle
    problem

    Number Juggle

    Age
    7 to 11
    Challenge level
    Fill in the missing numbers so that adding each pair of corner numbers gives you the number between them (in the box).
  • A Rod and a Pole
    problem

    A Rod and a Pole

    Age
    7 to 11
    Challenge level
    A lady has a steel rod and a wooden pole and she knows the length of each. How can she measure out an 8 unit piece of pole?
  • Three white dice on a yellow background.
    problem

    Add 3 Dice

    Age
    7 to 11
    Challenge level

    Three dice are placed in a row. Find a way to turn each one so that the three numbers on top of the dice total the same as the three numbers on the front of the dice. Can you find all the ways to do this?

  • Next Number
    problem

    Next Number

    Age
    7 to 11
    Challenge level
    Find the next number in this pattern: 3, 7, 19, 55 ...
  • Rocco's Race
    problem

    Rocco's Race

    Age
    7 to 11
    Challenge level
    Rocco ran in a 200 m race for his class. Use the information to find out how many runners there were in the race and what Rocco's finishing position was.
  • Throw a 100
    problem

    Throw a 100

    Age
    7 to 11
    Challenge level
    Can you score 100 by throwing rings on this board? Is there more than way to do it?
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