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NRICH: Making Maths: Snake Pits

A game to make and play based on the number line.

Age 5 to 14

Here’s a great game that you can make and then play with a friend. It’s called Snake Pits.

To make “Snake Pits”

You’ll need:

• 2 pieces of A4 card (or stiff paper)
• Cocktail stick
• Felt pen or marker
• Scissors
• Ruler
• Glue
1. On one piece of card, you need to draw a number line from 0 to 15, including the half numbers i.e. 0,12,1,112,2,... and so on. To make this number line as big as possible it is better to do it in three parts. Click here to see an example with instructions, which you can print off or copy.
2. At the top of the other piece of card draw a ring, big enough to fit around a number on the number line. Cut it out very carefully. Use this ring as a template and draw 9 more, so that altogether you have 10 rings. Click here to see an example. Don’t waste the card because you’ll need about half of it for the next stage!
3. The next stage is to make a spinner. If you click here you will find one drawn for you. You could print it off and cut it out, or copy it onto the rest of your card.
4. Carefully push the cocktail stick through the centre of the spinner. You may need to ask an adult to help.
There! You’re ready to play the game now. Here’s how:

To play “Snake Pits”:

You’ll need:

• Fraction number line
• Spinner
• 10 rings of card
• 10 counters (5 each of two different colours)
• Pencil and paper

The aim of the game is to use as few counters as possible to reach 15 on the number line.

How to play:

1. Place the 10 rings around any 10 numbers on the number line, except 0 and 15. These ringed numbers are the snake pits. If you land on a pit, you lose that counter and must replace it with another out of your set of 5. (You don’t need to start back at 0.)
2. Each person has 5 counters of the same colour.
3. Both players start with one of their counters on 0: one player’s counter above the number line and the other’s below.
4. The first player spins the spinner twice. He or she may like to write down both the numbers.
5. This player must decide which number to use for their turn. They should move their counter along the number line by the right amount, trying to stay clear of the snake pits!
6. The second player then has a turn and so on.
7. To finish, you must wait until you can land exactly on 15.
8. Remember, the winner is not the person to finish first, but the player who loses fewer counters on the way.

You can make the game a little bit different by:

• Starting at 15 and jumping backwards
• Making new number lines, for example labelled in quarters or thirds, and altering the numbers on the spinner to 0, 1 /4 , 1 /2 , 3 /4 and 1 or 0, 1 /3 , 2 /3 and 1.

This problem has been adapted from the book “Using Number Lines with 5-8 year olds” by Fran Mosley, published by BEAM Education. This book is out of print but can still be found on Amazon.

Fractions & Decimals, Number Values & Counting
K-6, Middle School, High School

## Organization

NRICH (University of Cambridge)

Board/Card Game
Tutorial