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Have you noticed that some very long numbers are very big whilst other very long numbers are small? Can you think of an example of each?
Here's a game where you can test your skill at putting small numbers into the right order - it's not as easy as it sounds!
How to play
You need a partner, a copy of the game board, and two different coloured pencils.
Decide who goes first.
Take turns to choose a number from the grid and mark it on the spiral. Make sure you know where 0 and where 1 is!
Keep taking turns until one of you has marked three numbers next to each other.
Can you work out a winning strategy?
Does it matter who goes first?
Does it matter which number you choose first?
Can you make up a different set of numbers which would make the game more challenging?
Perhaps you could have different start and end numbers for your spiral?
Send us your ideas so that we can share them with other children.
Why play this game?Ordering decimal numbers, especially those between 0 and 1, can be quite tricky especially if children hold the common misconception that the longer a number, the bigger it is. By placing numbers on a spiral rather than a straight line, children are helped to focus on the order of the numbers, ie their relative positions, rather than trying to work out their size. The game element means they practise a very large number of comparisons, whilst the more confident players can focus on trying to develop a winning strategy.
Possible approachDraw a large spiral on the white board, marking 0 in the middle and 1 on the outside. Ask a willing child to come and mark where they think 0.5 might be. Discuss how the spiral makes it difficult to know exactly where to put it, but that's not important - what matters here is that 0.5 is somewhere reasonably near the middle of 0 and 1.
Key questionsWhere will you place this number?
Possible extensionGiven free rein, you may be surprised at the numbers children choose for their own games. For a really difficult variation, and for children who are confident with negative numbers, try a spiral from -1 to 1.
Possible supportUse the game board B which uses numbers with one decimal place and a spiral from 0 to 2.
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