Copyright © University of Cambridge. All rights reserved.

'Sorting Logic Blocks' printed from http://nrich.maths.org/

Show menu

Sorting Logic Blocks


Choose a kind of rule, like "only have four-sided shapes"  or "only have large shapes".
Challenge someone else to work out your "rule".
They can do this by chosing a shape, for you to say either ,
"Yes, that obeys my rule and is in my set" (you put it over on the left),
or
"No, this does not obey my rule and so is not in my set" (you put it over on the right).

How did you decide which shapes to choose?
Did you get quicker at finding out the rule?
What was the smallest number of shapes you needed to try?
Could you make some more shapes to add to the set? What would you make and why?

 Tell us about some of the rules you chose and how you decided which shapes to try.
 
 Full screen version 
 
This text is usually replaced by the Flash movie.
 
 

Why do this activity?
This interactivity can be used to build up children's confidence with the language associated with 2D shape. 

Possible approach
You can use the interactivity as a whole class, teacher-led activity, for example by choosing a particular property and dragging a shape which meets that criteria to the left of the screen underneath 'These shapes are in my set'.
The first time you do this it's a good idea to conduct it in silence. Children take turns to come to the front and select a shape. Without saying anything, you drag it to the appropriate side of the screen. When they think they know your rule they could write it down on their whiteboards.

Once they become familiar with the game, you can interrogate them about their choices.  'Why did you choose that one?' 'I'll put that one here - what does that tell you?'

You could then challenge the children to use as few shapes as possible to test their ideas.  In this way, you can use the same interactivity to highlight different properties of shapes so it can be returned to many times over the course of an academic year.

Key Questions
Why did you choose that one?
I'll put that one here - what does that tell you?
Which would be a good one to choose now? Why?

Possible extension
If you have sets of logiblocks available (they have gone out of fashion a little but they may be hiding in the back of a cupboard ...) then children could play this game in pairs. One child writes down a rule before they begin playing. Together they set out the pieces as in the interactivity and decide where they will place those that are, and those that aren't, in the rule. Then they swap. What is the least number of shapes they could offer before they stated the rule correctly?

Possible support

For a class that is less confident, you could scaffold their learning by writing several different rules on the board. They then know that your rule is one of those and can choose accordingly. Children could make up their own rule for you to write.