Year 8 Explaining, convincing and proving

  • Subtraction Surprise
    problem
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    Subtraction Surprise

    Age
    7 to 14
    Challenge level
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    Try out these calculations. Are you surprised by the results?

  • An American flag waving in the wind.
    problem
    Favourite

    American Billions

    Age
    11 to 14
    Challenge level
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    Play the divisibility game to create numbers in which the first two digits make a number divisible by 2, the first three digits make a number divisible by 3...

  • Isosceles Triangles
    problem
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    Isosceles Triangles

    Age
    11 to 14
    Challenge level
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    Draw some isosceles triangles with an area of $9cm^2$ and a vertex at (20,20). If all the vertices must have whole number coordinates, how many is it possible to draw?

  • Triangles in circles
    problem
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    Triangles in Circles

    Age
    11 to 14
    Challenge level
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    Can you find triangles on a 9-point circle? Can you work out their angles?

  • Flippin' discs
    problem
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    Flippin' Discs

    Age
    11 to 14
    Challenge level
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    Discs are flipped in the air. You win if all the faces show the same colour. What is the probability of winning?

  • problem
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    Reaction Timer

    Age
    11 to 14
    Challenge level
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    This problem offers you two ways to test reactions - use them to investigate your ideas about speeds of reaction.

  • Crossed Ends
    problem
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    Crossed Ends

    Age
    11 to 14
    Challenge level
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    Crosses can be drawn on number grids of various sizes. What do you notice when you add opposite ends?

  • problem
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    How Would You Score It?

    Age
    11 to 14
    Challenge level
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    Invent a scoring system for a 'guess the weight' competition.

  • A ring of Jacks, Queens and Kings on a green table.
    problem
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    Sociable Cards

    Age
    11 to 14
    Challenge level
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    Move your counters through this snake of cards and see how far you can go. Are you surprised by where you end up?

  • What numbers can we make?
    problem
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    What Numbers Can We Make?

    Age
    11 to 14
    Challenge level
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    Imagine we have four bags containing a large number of 1s, 4s, 7s and 10s. What numbers can we make?

  • Olympic Records
    problem
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    Olympic Records

    Age
    11 to 14
    Challenge level
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    Can you deduce which Olympic athletics events are represented by the graphs?

  • Place your orders
    problem
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    Place Your Orders

    Age
    11 to 14
    Challenge level
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    Can you rank these sets of quantities in order, from smallest to largest? Can you provide convincing evidence for your rankings?

  • Olympic Measures
    problem
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    Olympic Measures

    Age
    11 to 14
    Challenge level
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    These Olympic quantities have been jumbled up! Can you put them back together again?

  • Triangles in a Square
    problem
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    Triangles in a Square

    Age
    11 to 14
    Challenge level
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    What are the possible areas of triangles drawn in a square?

  • Polygon Rings
    problem
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    Polygon Rings

    Age
    11 to 14
    Challenge level
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    Join pentagons together edge to edge. Will they form a ring?

  • Gabriel's Problem
    problem
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    Gabriel's Problem

    Age
    11 to 14
    Challenge level
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    Gabriel multiplied together some numbers and then erased them. Can you figure out where each number was?

  • Coordinate Patterns
    problem
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    Coordinate Patterns

    Age
    11 to 14
    Challenge level
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    Charlie and Alison have been drawing patterns on coordinate grids. Can you picture where the patterns lead?

  • All in a jumble
    problem
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    All in a Jumble

    Age
    11 to 14
    Challenge level
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    My measurements have got all jumbled up! Swap them around and see if you can find a combination where every measurement is valid.

  • Power mad!
    problem
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    Power Mad!

    Age
    11 to 14
    Challenge level
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    Powers of numbers behave in surprising ways. Take a look at some of these and try to explain why they are true.

  • Always a multiple?
    problem
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    Always a Multiple?

    Age
    11 to 14
    Challenge level
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    Think of a two digit number, reverse the digits, and add the numbers together. Something special happens...

  • Who's the best?
    problem
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    Who's the Best?

    Age
    11 to 14
    Challenge level
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    Which countries have the most naturally athletic populations?

  • Non-Transitive Dice
    problem
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    Non-Transitive Dice

    Age
    11 to 14
    Challenge level
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    Alison and Charlie are playing a game. Charlie wants to go first so Alison lets him. Was that such a good idea?

  • Fibonacci Surprises
    problem
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    Fibonacci Surprises

    Age
    11 to 14
    Challenge level
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    Play around with the Fibonacci sequence and discover some surprising results!

  • Unequal Averages
    problem
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    Unequal Averages

    Age
    11 to 14
    Challenge level
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    Play around with sets of five numbers and see what you can discover about different types of average...

  • Four playing cards on top of each other. Each card shows a different ace.
    problem
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    Snappy Statements

    Age
    11 to 14
    Challenge level
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    Use properties of numbers to work out whether you can satisfy all these statements at the same time.

  • Consecutive negative numbers
    problem
    Favourite

    Consecutive Negative Numbers

    Age
    11 to 14
    Challenge level
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    Do you notice anything about the solutions when you add and/or subtract consecutive negative numbers?

  • the greedy algorithm
    problem
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    The Greedy Algorithm

    Age
    11 to 14
    Challenge level
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    The Egyptians expressed all fractions as the sum of different unit fractions. The Greedy Algorithm might provide us with an efficient way of doing this.

  • Multiple Surprises
    problem
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    Multiple Surprises

    Age
    11 to 16
    Challenge level
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    Sequences of multiples keep cropping up...

  • Robotic Rotations
    problem
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    Robotic Rotations

    Age
    11 to 16
    Challenge level
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    How did the the rotation robot make these patterns?