Lines of symmetry – Year 4 maths lesson
Lesson 28 of 31 in the Year 4 maths course
UK version. UK school years, UK spelling and pounds (£). · US Math Department
A complete 45-minute lesson for Year 4 (ages 8–9) that runs on this page – at school or at home. Every answer is marked straight away, with a worked explanation.
- Time
- 45 minutes + 20 min homework
- Year
- Year 4 (ages 8–9)
- You need
- Paper, a pencil and this page
- Marked
- Instantly, with explanations
For parents: how to use this lesson
You don't need to know this topic yourself. The lesson explains each step on screen, one tidy step at a time. Every answer is marked straight away with a worked explanation, so you never have to mark anything.
- Read what your child will learn and the big ideas together.
- Press Start the lesson below and sit with your child for the teaching and the worked examples (about 19 minutes).
- Let them do the practice on their own. They choose Getting started, On track or Challenge – start on On track and move up after a few right in a row.
- Finish with the exit ticket and the talk question: “How many lines of symmetry does a circle have?”
- Later that day or the next day: the homework (20 minutes), then a practice test.
Watch out for
- Thinking a diagonal of a rectangle is a line of symmetry. Fold a paper rectangle along the diagonal: the halves do not match.
- Only looking for up-and-down lines. Check across and diagonally too.
Tip for home: Look for symmetry in leaves, butterflies, faces and letters.
What your child will learn
We are learning to find lines of symmetry and complete symmetrical shapes.
Success looks like
- I can find lines of symmetry.
- I can complete a symmetrical shape.
- I can say how many lines of symmetry a shape has.
Key words
- symmetry
- when one half mirrors the other
- line of symmetry
- the fold line where halves match
- mirror line
- another name for a line of symmetry
- reflect
- flip over a line
What to have ready
- Paper and a pencil
- This page on a computer, tablet or phone
- For the hands-on part: Fold paper shapes to find lines of symmetry. Use a mirror on half a picture to see the whole.
The big ideas (for the adult)
A line of symmetry splits a shape into two halves that are mirror images.
If you fold a shape along a line of symmetry, the two halves match exactly.
Some shapes have several lines of symmetry; some have none. A regular shape has as many lines of symmetry as sides.
The lesson, step by step
| Part | Time | How it is checked |
|---|---|---|
| Starter: quick recall | 5 min | Marked by Classfern |
| Teaching input | 10 min | Not assessed, self-checked |
| Worked examples and guided practice | 9 min | Not assessed, marked by Classfern |
| Independent practice | 15 min | Marked by Classfern |
| Plenary and exit ticket | 6 min | Marked by Classfern, self-checked |
Starter, "your turn", practice and exit ticket are marked by Classfern. Worked examples and teaching are not assessed. The hands-on task and the reflection are self-assessed. Explanations in talk are judged by the parent and not recorded.
The lesson
It runs here on the page. No sign-up and no names – progress is kept only in this browser.
Homework and practice at home
20 minutes: 10 practice questions, 3 multiple-choice questions and 2 to remember from earlier work, then a short reflection. New questions every time, all marked instantly.
More practice
More Year 4 maths lessons
- Place value: the value of each digit
- Rounding to the nearest 10, 100 or 1,000
- One more, one less, ten more and ten less
- Number lines
- Comparing, ordering and writing numbers
- Roman numerals
- Column addition
- Column subtraction
- Times tables
- Short multiplication
- Multiplying and dividing by 10, 100 and 1,000
- Multiplication and division
- Solving word problems
- Equivalent fractions
- Adding and subtracting fractions with the same denominator
- Fractions of amounts
- Decimals: tenths, hundredths and thousandths
- Tenths and hundredths
- Rounding decimals
- Fractions, decimals and percentages
- Area of rectangles
- Perimeter
- Converting units of time
- Money: totals and change
- The 24-hour clock
- Types of angles and measuring angles
- Properties of 2-D shapes
- Coordinates
- Bar charts, pictograms and tables
- Line graphs
Curriculum
National Curriculum for England, Year 4: “identify lines of symmetry in 2-D shapes presented in different orientations”
National Curriculum for England, Year 4: “complete a simple symmetric figure with respect to a specific line of symmetry”
Contains public sector information licensed under the Open Government Licence v3.0.
Our lessons and questions are our own. They are not written or endorsed by any government department, testing agency or exam board.