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Guess the Dominoes


This is one of a series of problems designed to develop learners' team working skills. Other tasks in the series can be found by going to this article.
image of dominoes

What are you aiming to do?

For the task:

The team has to find the rule on the Ruler's card, using the minimum number of tests. A test is asking whether a particular domino obeys the rule.

As a team:

  • finding out what others think
  • giving reasons for ideas
  • being concise
  • reflecting on what has been said
  • allowing everyone to contribute.

Getting started

The team can be made up of four or five people of which one person is chosen to be the "Ruler". If you do the task several times, members of the team can take turns at being the Ruler. You may also wish to appoint an observer.
You will need:

Tackling the problem

  • The team has the set of domino cards.
  • The Ruler selects a rule card from the pack and keeps it hidden from the rest of the team.
  • Before deciding on a domino to present to the Ruler for testing - the team must discuss and agree as a team why they think it would make a good test case.
  • If the domino obeys the rule then the Ruler puts it in the Box, if it does not obey the rule it is placed outside the Box.
  • If someone thinks they know the rule, they must share their reasoning with the rest of the team, who discuss and check their reasoning before deciding if it is a suitable conjecture to put forward.
  • The Ruler then reveals the rule.
  • If the team is right the task can start again with a different Ruler. If they are wrong they discuss where their error in reasoning may have been before moving on.
At the end of the task discuss how well you worked as a team.

Team and Ruler Guidelines

  • No one should choose a domino for testing without the agreement of the rest of the team.
  • You are trying to find the rule by testing the minimum number of dominoes.
  • The Ruler can only put a chosen domino in the Box or outside it.
  • The Ruler can only speak to state whether the rule the team have decided on is correct or not.

Observer Guidelines

  • Make a note of how often each member of the team contributes to the discussion.
  • Check that the Ruler only tests a domino that has been chosen by the agreement of the whole team.
  • Look for occasions when someone asks someone else's opinion.
  • Look for occasions when someone listens and responds to someone else's ideas.

Why do this problem?

This task encourages learners to ensure all members of the team participate, share their reasoning, listen to each other's opinions and reflect on the outcome. This is one of a series of problems designed to develop learners' team-working skills. Other tasks in the series can be found by going to this article.


Possible approach

The task is designed to work with teams of four, taking it in turns to be "The Ruler".

Using a fifth person as an observer means that feedback can be very specific and works well either using another learner or an adult.

The aim is for the team to discuss and agree before selecting any domino to be tested by The Ruler. Does the domino obey the rule on the chosen rule card?

Here are the domino cards in colour (to double nine) and here they are in black and white.
Use the rule cards in this document.
Guideline cards for the team and Ruler and Observer can be used to focus the learners' attention on the main aims of the task.

One of the roles of the Observer is to check discussion takes place before a decision is made and that the Ruler only responds if they feel everyone has contributed to the decision.

When teams have finished working on the task it is important that they spend time discussing in groups, and then as a whole class, how well they worked as a team. They can consider what they have learned from the experience and what they would do differently next time, particularly in terms of how to listen to each other and ensure that all members of the team participate. Your own observations, as well as those of observers, might inform the discussions.


Key questions

  • Was there a choice of domino to test that was particularly useful? Why?
  • Were there any ideas that proved really helpful?
  • How well did you listen to others in your group?
  • How did you ensure that everyone had a chance to contribute?

Possible extension

Choose two rule cards and only put dominoes in the Box that obey both rules. Learners may like to try one of the other 'Guess the rule' tasks, which can be found by going to this article.

Possible support

You may wish to give a copy of all, or a selection, of the rule cards to the team as well as the Ruler so they have a list of possible rules. You may also wish to reduce the number of dominoes rather than using the full set of double blank to double nine.
Other team-building tasks can be found by going to this article.