How to Win Matchstick Maths Game, 'Nim' - Fun for Children
The MatchStick Game - also known as 'Nim'
Here is a simple game for 2 people that you can always win (unless your opponent also knows the secret).
It’s a tremendous confidence booster for children who can learn to defeat adults once they learn the 'trick'. Kid's love secrets; particularly ones adults don't know.
You start off with 15 matches laid out on the ground. In practice you can use any small objects. Stones or shells are ideal which means it is a great game to introduce on the beach when the kids are getting restless.
The rules are very simple. Each person takes turns to remove either 1, 2 or 3 matches. You win if your opponent is left with the last match.
An Example Game
Number of Matches
Number of Matches Removed
Number of matches Left
You remove 2
Opponent removes 3
You remove 1
Opponent removes 2
You remove 2
Opponent removes 1
You remove 3
1 Opponent looses!
How Does it Work?
When you start, you first remove 2 matches. You are then guaranteed to win.
From then on, each time your opponent plays you make the count removed by you and your opponent up to 4. If they take 1 you take 3 if they take 2 you take 2 etc. This means your opponent is always left with the last match.
The key to this game is TARGET NUMBERS. You arrange it so you leave your opponent with:
13, 9, 5 and finally 1 match.
Once you've removed the first 2 matches, you keep making up the total removed in that round to 4.
Can you win if your opponent starts? Yes you can unless they understand how to win and begin with 2.
If they start with 1: you take away another 1 bringing you to your target number of 13 left.
If they start with 3, you remove another 3 making the target number 9.
A simple game like this is an example of what mathematicians call an Impartial, two-person game with Complete Information.
Impartial means that rules for moving apply equally to both players (unlike Chess, for example, which not impartial, because the white player can only move white pieces, and black can only move black pieces).
Complete information means that both players know the complete state of the game, in contrast to, for example, card games such as poker where one player does not know the cards held by the other player(s).
What if They Start and Remove 2?
Then you play randomly and try to reach a target number.
START: 15 Matches
Opponent removes 2 matches (leaving 13)
You remove 2 (leaving 11)
Opponent removes 1 (leaving 10)
You can then remove 1 (leaving 9 - target number). You can now win.
Unless your opponent understands the trick they are almost certainly going to make a mistake and allow you to reach a target number before the end of the game.
Now you've mastered the game, try it out on your friends and your children. But remember, don't use your new found skills to cheat strangers in bars or pubs to buy you drinks. This could be illegal where you live and besides, you might make some powerful enemies!
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- If You Are Into Games Theory, Find Out More on Wikipedia
This is a clever stuff and not for the faint hearted!
- Hub About Bedtime Games for Kids
© 2008 Rik Ravado