Year 10 Explaining, convincing and proving

  • Differences
    problem
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    Differences

    Age
    11 to 14
    Challenge level
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    Can you guarantee that, for any three numbers you choose, the product of their differences will always be an even number?

  • Arithmagons
    problem
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    Arithmagons

    Age
    11 to 16
    Challenge level
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    Can you find the values at the vertices when you know the values on the edges?

  • Take Three From Five
    problem
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    Take Three From Five

    Age
    11 to 16
    Challenge level
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    Caroline and James pick sets of five numbers. Charlie tries to find three that add together to make a multiple of three. Can they stop him?

  • Same length
    problem
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    Same Length

    Age
    11 to 16
    Challenge level
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    Construct two equilateral triangles on a straight line. There are two lengths that look the same - can you prove it?

  • Where is the dot?
    problem
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    Where Is the Dot?

    Age
    14 to 16
    Challenge level
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    A dot starts at the point (1,0) and turns anticlockwise. Can you estimate the height of the dot after it has turned through 45 degrees? Can you calculate its height?

  • Making sixty
    problem
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    Making Sixty

    Age
    14 to 16
    Challenge level
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    Why does this fold create an angle of sixty degrees?

  • Curvy areas
    problem
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    Curvy Areas

    Age
    14 to 16
    Challenge level
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    Have a go at creating these images based on circles. What do you notice about the areas of the different sections?

  • circles in quadrilaterals
    problem
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    Circles in Quadrilaterals

    Age
    14 to 16
    Challenge level
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    Explore when it is possible to construct a circle which just touches all four sides of a quadrilateral.

  • A little light thinking
    problem
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    A Little Light Thinking

    Age
    14 to 16
    Challenge level
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    Here is a machine with four coloured lights. Can you make two lights switch on at once? Three lights? All four lights?

  • Last one standing
    problem
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    Last One Standing

    Age
    14 to 16
    Challenge level
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    Imagine a room full of people who keep flipping coins until they get a tail. Will anyone get six heads in a row?

  • problem
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    Who's the Winner?

    Age
    14 to 16
    Challenge level
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    When two closely matched teams play each other, what is the most likely result?

  • Nutrition and Cycling
    problem
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    Nutrition and Cycling

    Age
    14 to 16
    Challenge level
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    Andy wants to cycle from Land's End to John o'Groats. Will he be able to eat enough to keep him going?

  • Olympic Triathlon
    problem
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    Olympic Triathlon

    Age
    14 to 16
    Challenge level
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    Is it the fastest swimmer, the fastest runner or the fastest cyclist who wins the Olympic Triathlon?

  • Picturing the world
    problem
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    Picturing the World

    Age
    14 to 16
    Challenge level
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    How can we make sense of national and global statistics involving very large numbers?

  • Box plot match
    problem
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    Box Plot Match

    Age
    14 to 16
    Challenge level
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    Match the cumulative frequency curves with their corresponding box plots.

  • Isosceles Seven
    problem
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    Isosceles Seven

    Age
    14 to 16
    Challenge level
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    Is it possible to find the angles in this rather special isosceles triangle?

  • Terminology
    problem
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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?

  • Inscribed in a Circle
    problem
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    Inscribed in a Circle

    Age
    14 to 16
    Challenge level
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    The area of a square inscribed in a circle with a unit radius is 2. What is the area of these other regular polygons inscribed in a circle with a unit radius?

  • Painted Cube
    problem
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    Painted Cube

    Age
    14 to 16
    Challenge level
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    Imagine a large cube made from small red cubes being dropped into a pot of yellow paint. How many of the small cubes will have yellow paint on their faces?

  • Multiplication square
    problem
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    Multiplication Square

    Age
    14 to 16
    Challenge level
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    Pick a square within a multiplication square and add the numbers on each diagonal. What do you notice?

  • Triangle in a Triangle
    problem
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    Triangle in a Triangle

    Age
    14 to 16
    Challenge level
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    Can you work out the fraction of the original triangle that is covered by the inner triangle?

  • Nicely Similar
    problem
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    Nicely Similar

    Age
    14 to 16
    Challenge level
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    If the hypotenuse (base) length is 100cm and if an extra line splits the base into 36cm and 64cm parts, what were the side lengths for the original right-angled triangle?

  • Gutter
    problem
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    Gutter

    Age
    14 to 16
    Challenge level
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    Manufacturers need to minimise the amount of material used to make their product. What is the best cross-section for a gutter?

  • For richer for poorer
    problem
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    For Richer for Poorer

    Age
    14 to 16
    Challenge level
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    Charlie has moved between countries and the average income of both has increased. How can this be so?

  • Speeding boats
    problem
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    Speeding Boats

    Age
    14 to 16
    Challenge level
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    Two boats travel up and down a lake. Can you picture where they will cross if you know how fast each boat is travelling?

  • Pythagoras Perimeters
    problem
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    Pythagoras Perimeters

    Age
    14 to 16
    Challenge level
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    If you know the perimeter of a right angled triangle, what can you say about the area?

  • Puzzling Place Value
    problem
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    Puzzling Place Value

    Age
    14 to 16
    Challenge level
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    Can you explain what is going on in these puzzling number tricks?

  • Latin Numbers
    problem
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    Latin Numbers

    Age
    14 to 16
    Challenge level
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    Can you create a Latin Square from multiples of a six digit number?

  • Compare Areas
    problem
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    Compare Areas

    Age
    14 to 16
    Challenge level
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    Which has the greatest area, a circle or a square, inscribed in an isosceles right angle triangle?