The note
How schools teach it now
Children fold paper shapes and use mirrors to find lines of symmetry, then complete shapes on squared paper by counting squares to the mirror line. A regular polygon has as many lines of symmetry as it has sides.
5-minute kitchen-table activity
Fold paper and cut out a shape. Before opening, your child predicts what it will look like. Then stand a mirror on the letters of their name: which letters look the same?
Worked example
How many lines of symmetry does a regular hexagon have?
- A regular polygon has as many lines of symmetry as sides.
- Check: 3 lines go corner to corner and 3 go through the middles of opposite sides.
Answer: 6
Common mistakes to watch for
- Counting a rectangle's diagonal as a line of symmetry (it isn't).
- Forgetting a square's diagonal lines (it has 4 lines in total).
- Copying the shape across instead of flipping it.
Encouragement
- Try saying
- “Imagine folding it. Would the two halves match exactly?”
- Rather than
- “Look, it's obvious.”