Creating and manipulating expressions and formulae

  • Plus Minus
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    Plus Minus

    Age
    14 to 16
    Challenge level
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    Can you explain the surprising results Jo found when she calculated the difference between square numbers?

  • Sitting Pretty
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    Sitting Pretty

    Age
    14 to 16
    Challenge level
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    A circle of radius r touches two sides of a right angled triangle, sides x and y, and has its centre on the hypotenuse. Can you prove the formula linking x, y and r?

  • Of all the areas
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    Of All the Areas

    Age
    14 to 16
    Challenge level
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    Can you find a general rule for finding the areas of equilateral triangles drawn on an isometric grid?

  • Fair Shares?
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    Fair Shares?

    Age
    14 to 16
    Challenge level
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    A mother wants to share some money by giving each child in turn a lump sum plus a fraction of the remainder. How can she do this to share the money out equally?

  • What's Possible?
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    What's Possible?

    Age
    14 to 16
    Challenge level
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    Many numbers can be expressed as the difference of two perfect squares. What do you notice about the numbers you CANNOT make?

  • Why 24?
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    Why 24?

    Age
    14 to 16
    Challenge level
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    Take any prime number greater than 3 , square it and subtract one. Working on the building blocks will help you to explain what is special about your results.

  • Number rules - OK
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    Number Rules - OK

    Age
    14 to 16
    Challenge level
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    Can you produce convincing arguments that a selection of statements about numbers are true?

  • Terminology
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    Terminology

    Age
    14 to 16
    Challenge level
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    Given an equilateral triangle inside an isosceles triangle, can you find a relationship between the angles?

  • Pick's Theorem
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    Pick's Theorem

    Age
    14 to 16
    Challenge level
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    Polygons drawn on square dotty paper have dots on their perimeter (p) and often internal (i) ones as well. Find a relationship between p, i and the area of the polygons.

  • Perfectly Square
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    Perfectly Square

    Age
    14 to 16
    Challenge level
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    The sums of the squares of three related numbers is also a perfect square - can you explain why?