What are 2D and 3D Shapes? — Understanding the Basics at KS1

2D and 3D shapes are an important topic in KS1 maths and come up both in Year 1 and Year 2. That’s why we’ve put together this brief overview for parents. But if you’d like to read the full article, we invite you to do so here.

2D and 3D shapes worksheets

Click here for free primary school 2D and 3D shapes worksheets.

What is a 2D shape?

2D shapes have two dimensions — height and width. It can be hard to find them in real life, but shadows and reflections can be useful examples when explaining the concept to children. Drawings also have two dimensions; they cannot be picked up off the page.

What is a 3D shape?

A 3D shape has three dimensions — height, width, and depth. Because of their depth, you can pick them up and hold them. Even seemingly flat things are, in reality, three-dimensional. You can pick up the paper a drawing is on, even though you cannot pick up the drawing itself.

What are the differences between 2D and 3D shapes?

A 3D shape is a 2D shape with depth. For example, a cube is a square that, in addition to height and width, also has depth.

Other 2D shapes can be made 3D in several different ways. For example, a triangle could become different kinds of pyramid or even a prism.

Properties of 2D shapes

2D shapes have height and width, but they also have sides and corners where the sides meet.

2D shapes may have the same number of sides and corners, but still be different shapes. A square, for example, is a special kind of rectangle, one where all the sides are the same length.

Using terminology that is taught at Key Stage 1, a square is a “regular” shape because all its sides are the same length and all its angles are equal. A rectangle is an “irregular” shape.

Other shapes might have both regular and irregular forms — a regular triangle, for example, is an equilateral triangle, where all sides are the same length. All other triangles are irregular.

Properties of 3D shapes

Instead of sides and corners, 3D shapes have faces, edges and vertices. A face is usually the flat section of a shape, an edge is found where faces meet, and vertices are the points at which edges meet.

Like squares and rectangles, a cube is a regular cuboid, and all other cuboids are irregular.

2D and 3D shapes in Key Stage 1

Year 1

In Year 1, pupils learn to recognise and name the most common 2D and 3D shapes. They will handle and name a range of shapes, and learn to recognise that rectangles, triangles, cuboids and pyramids are not always similar to each other.

Year 2

In Year 2, pupils learn about 2D and 3D shapes’ properties and learn to recognise and count sides, edges, vertices and faces. They will also learn to identify 2D shapes on the surfaces of 3D shapes, as well as lines of symmetry. They will also learn about new shapes, such as polygons and cones.

2D and 3D shapes are important for later learning too, so students must gain a solid foundation in Key Stage 1.