Math // Geometry

Sorting 2-D and 3-D shapes

Compare and sort common 2-D and 3-D shapes and everyday objects by their properties

Ages
6 to 7
Type
Method
Builds on
2 topics
Leads to
0 topics
Standards
1 code

Quick check

Can the learner sort a collection of shapes into groups — for example, separating all the shapes with curved sides from those with only straight sides?

Ask this to see whether the topic is secure.

Topic // Mastery

What mastery looks like

What a learner can do once this topic is secure.
  • Sort a collection of 2-D shapes by number of sides
  • Sort 3-D shapes by number of faces or whether faces are flat/curved
  • Explain criteria used to sort a group of shapes

Topic // Map

Where this fits

What to learn first and what this topic opens up, with the reason for each link. Required links come first.
  • RequiredMust come first
  • HelpfulHelps, but not essential

Before this

2 topics

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Sorting 2-D and 3-D shapes

Ages 6 to 7 // Method

Leads to

0 topics

Nothing in the catalogue builds on this topic yet. Browse Geometry

Topic // Research-informed

Teaching notes

From the Marble Skill Taxonomy. These notes have not been validated in classrooms, so treat them as a starting point for your own judgement.

The approach

Children aged 6-7 learn to compare and sort a mixed collection of 2-D shapes, 3-D solids and everyday objects by geometric PROPERTIES — number of sides, number/type of faces, flat vs curved surfaces, number of vertices — and to articulate the criterion used. The procedural goal is a consistent, property-based sort: choose one attribute, apply it to every item, then re-sort the SAME collection a different way. This builds on knowing the properties and pushes children off the van Hiele visual level, where they group by overall look, colour or size. Best taught with real shapes to handle, 'is / is not' two-set sorting, and 'guess my rule' games.

Common misconceptions

  • Sorts by a non-defining feature — colour, size or overall look — rather than a geometric property.
  • Groups shapes by holistic resemblance ('these look the same') and cannot state a single consistent rule, letting the rule drift mid-sort.
  • Miscounts sides, faces or vertices — losing track of where counting started — so shapes end up in the wrong group.
  • Can sort one way but cannot re-sort the same collection by a different property, or cannot infer the rule of a set sorted by someone else.

Useful representations

  • A mixed tray of handleable 2-D shapes and 3-D solids plus everyday objects
  • Two sorting hoops / Carroll or Venn two-set frame labelled with an 'is / is not' criterion
  • Wipe-clean pen for marking faces/edges/vertices while counting
  • 'Guess my rule' pre-sorted sets

Teaching practices

  • Sort a physical, mixed collection into two sets on an 'is / is not' criterion (e.g. has a curved surface / has no curved surface), then challenge children to re-sort the SAME set a different way.
  • Play 'guess my rule': present a set already sorted by someone else and have children infer the property used — this makes the criterion explicit.
  • Insist the rule is a geometric property; when a child groups by colour or size, restrict the set to one colour/size so appearance cannot be the criterion.
  • Hand children real solids to handle and mark faces/edges/vertices with a wipe-clean pen as they count, so a sort by 'number of faces' rests on an accurate count.
  • Model articulating the rule aloud ('all of these have a triangular face') and ask 'does EVERY shape in this group follow your rule?' to check consistency.

Activities to try

  1. 1

    Sort a real tray two ways on an 'is / is not' rule

    Why it works: A sort rests on one geometric property held constant and applied to every item; the same collection can be grouped validly in more than one way depending on which property you choose.

    1. Take a physical, mixed tray of handleable 2-D shapes, 3-D solids and everyday objects.
    2. Choose ONE geometric property as the rule (e.g. 'has a curved surface / has no curved surface') and place every item into one of two sorting hoops or a labelled two-set frame. Check that the rule makes sense for every item in the tray: a flat 2-D shape such as a circle has a curved side (edge) but no curved surface, so either agree how 2-D shapes are judged or pick a rule that fits both 2-D and 3-D items (e.g. 'has a curved edge or surface / has none').
    3. Say the rule aloud ('all of these have a curved surface') and check: does EVERY shape in this group follow my rule?
    4. Now scatter the SAME shapes and re-sort them by a different property (e.g. 'has a triangular face / has no triangular face'); notice which shapes move to a different hoop and why.
  2. 2

    Guess my rule

    Why it works: Making the hidden criterion explicit forces attention onto defining properties and shows that a good sort rests on one rule every member satisfies.

    1. Look at a set someone else has already sorted into two groups, with the rule hidden.
    2. Infer and state the geometric property that was used to make the two groups.
    3. Continue the sort by placing a few more shapes into the correct group, keeping the rule constant.
    4. Then set your own 'guess my rule' challenge for a partner.
  3. 3

    Count faces, edges and vertices accurately before sorting

    Why it works: A count-based sort is only as reliable as the count; marking each feature once prevents losing track and keeps the sort consistent.

    1. Hold a real solid and mark each face, edge or vertex with a wipe-clean pen as you count it, so you count each one exactly once.
    2. Record the count, then use it as the sorting rule (e.g. 'sort solids by number of faces' or 'six or more vertices / fewer than six vertices').
    3. Recount a solid a second way and check you get the same total; if not, find where you lost track.
    4. Place each solid in the correct group based on the verified count.

Topic // Standards

Curriculum standards

Codes for the curriculum statements this topic maps to. Each publisher owns its standard text.
The national curriculum in England: Key stages 1 and 2 framework document
Maths/Y2/GPS/4

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