# Spiralling Decimals for Two

Spiralling Decimals game for an adult and child. Can you get three decimals next to each other on the spiral before your partner?

## Problem

Here's a game to play with an adult!

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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 do you play?**

You'll need an adult to play with.

You'll also need 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.

0.5 | 0.25 | 0.75 | 0.3 |

0.35 | 0.9 | 0.99 | 0.999 |

0.1 | 0.01 | 0.05 | 1.79 |

0.64 | 0.32 | 0.54 | 0.865 |

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Can you work out a winning strategy?

Does it matter who goes first?

Does it matter which number you choose first?

**Notes for adults**

This game is to help children learn how decimals are ordered, without worrying about exactly where the decimals should go on a number line - only the order of the numbers matters in this game.

**Easier version:**try this version, with decimals with one decimal place which need to be placed between 0 and 2.

**Harder version:**encourage the child to make up a different set of numbers, with different start and end numbers for the spiral.

When you've completed a game, talk together about good strategies. Does it matter who goes first? Does it matter which number you choose first?

There's a group version of this game here.