Copyright © University of Cambridge. All rights reserved.
'Which Solid?' printed from http://nrich.maths.org/
Why do this problem?
aims to encourage learners to develop their ability to communicate their reasoning and to frame and ask questions. The task requires learners to make sense of their own understanding, be concise, listen and reflect on what has been said. 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
This task also supports the development of language asssociated with, and properties of, 3D shapes.
The task is designed to work with teams of four with one chosen, in turns, to find the unknown.
Using a fifth person as an observer means that feedback can be very specific and works well either using another learner or an adult.
are the solids cards.
Give the teams plenty of time to do the task, allowing every member of the team to take the role of trying to find an unknown.
The observer's role should include checking discussion takes place before an answer is given and keeping track of the number of questions.
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.
Finish the session by listing the key words associated with 3D shapes that arose whilst learners did the task.
- Was there a question that proved really useful in identifying the solid?
- How well did you listen to each other in your team?
- How did you ensure that everyone had a chance to contribute?
You may wish to keep the cards hidden from the person trying to find the rule. Learners may like to try one of the other 'What am I?' tasks, which can be found by going to this article.
Why not use real solids? Put them in a bag and ask one of the team members (not the person who is trying to guess the shape) to choose a solid from the bag. It is also possible to reduce the number of cards, perhaps focusing on prisms. Other skill-building tasks can be found by going to this article