### Teaching and Group Activities for Understanding

**Day 1 Teaching**

Watch a short BBC action clip about line symmetry. Establish a definition for a line of symmetry. Place 2-D shapes in centre of the class, along with long thin strips of paper. Choose a child to pretend to karate chop a shape to find the line(s) of symmetry, placing a strip of paper to show it. Do all of these shapes have a line of symmetry?**Group Activities**

-- Fold a picture along a line of symmetry; complete symmetrical pictures.

-- Children draw one half of a picture for a partner to complete symmetrically. Begin to explore shapes with two lines of symmetry.

**Day 2 Teaching**

Show and carefully describe a square, modelling appropriate vocabulary. Note that it is a polygon. Show and define regular polygons, e.g. with a pentagon, hexagon and octagon. Children choose and describe a shape for a partner to guess. Swap and repeat. Record key vocabulary. Show, define and name irregular shapes.**Group Activities**

-- Sort 2-D shapes in Venn diagrams according to children’s criteria.

**Day 3 Teaching**

What words can we use to name and describe 2-D shapes? Which have ‘square corners’? Remind children that these are called right angles. Draw more shapes, children describe them to a partner. Sort shapes using a Venn diagram.**Group Activities**

Use the ‘Don’t make a triangle’ in-depth problem-solving investigation below as today’s group activity.

Or, use these activities:

-- Children sort 2-D shapes into a Venn diagram according to two ‘secret’ criteria, with one shape placed as an ‘odd one out’. The rest of the group try to guess the sorting criteria and the odd one out.