Crib Sheet

Our daily guide to educational jargon, teaching methods and the strange things children may bring back from school as homework. If there is a particular aspect of your child's education you wish explaining, use the POL Ask an Expert service.


Classifying things

One of the basic skills children need to learn is that of classifying things - sorting them into groups (called 'sets' in mathematics) according to their properties.

You can break this down into several parts: 

  • Classifying things according to existing criteria.
  • Classifying things according to several criteria at once.
  • Learning that the same object can belong in several different sets, and how to choose the most appropriate classification.
  • Working out a classification system of their own.
  • What to do when their is no clear classification system to use.

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Here are some examples of each of these, with mini-activities you can do to explore some of them:

- Classifying things according to existing criteria.

Get a jumble of objects and sort them according to these classifications:

  • Living (animals, plants, people); dead; non-living (bricks, plastic, metal).
  • Things that come in pairs (hands, feet, socks, shoes, gloves, chopsticks).
  • White things - snow, milk, writing paper.

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What other criteria could you use?

Don't forget that you might need a set that consists of 'things that don't fit anywhere' (this is a trickier concept for some children to grasp than you might expect).

- Classifying things according to several criteria at once.

Choose some different objects. This time, sort them into sets that have more than one thing in common:

  • things to wear that are green.
  • things to drink that are clear (lemonade, water).
  • things that are alive that you might find in your home (people, pets... pests?)

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- Learning that the same object can belong in several different sets, and how to choose the most appropriate classification.

You will probably need to choose the objects, and the sets, for this investigation with a bit more care.

For instance, you might have a tin can, a dead fish, a pile of sand, a shell, a piece of plastic, a pair of wellingtons, and an umbrella. If the sets available are Rubbish, Things I might find on the beach, and Things I use when it rains, then it's obvious that some of the items will fit easily into each of the categories. But the dead fish, the tin can and the plastic might all be found on the beach and yet also be classed as rubbish.

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- Working out a classification system of their own.

This time, instead of telling the child the category and asking her which objects fit it, do the reverse - talk about the object and what it's like, and then decide on a category. You might find that you have seven objects and seven categories, in which case you will need to decide how to group them together better - or perhaps decide that there is no way of grouping them that isn't completely forced ('things that are black, green or white and that you find in the kitchen or garden...').

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- What to do when there is no clear classification system to use.

Sometimes categories are too subjective. For instance, a group of 'long things' sounds fine until you discover that one person thinks something is long, but another person is convinced that it is short. You'll probably need to choose some objects to discuss to make this clear. What does your child think you could do about it? One suggestion might be to change the category a bit - so 'long things' become 'things that are longer than my arm', for instance.


Maths in the National Curriculum

Helping with Maths Homework

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