Chapter 11 — Fun with Symmetry

Chapter 11 of the Class 4 Mathematics NCERT textbook (Maths Mela), "Fun with Symmetry", introduces students to lines of symmetry, mirror reflections, and tiling patterns through hands-on activities like ink blot designs, paper aeroplanes, and folding-and-cutting challenges. Students explore symmetry in shapes, numbers, letters, and nature. Download the PDF and read the summary and Q&A below to master every activity in this chapter.

• Line of Symmetry and Mirror Line — The chapter builds on symmetry concepts from Grade 3 and introduces the formal idea of a line of symmetry — the line that divides a shape or design into two equal halves. Students also learn to call it a mirror line or line of reflection. Activities like the ink blot design and paper aeroplane folding make this concrete.
• Mirror Games with Shapes, Numbers, and Letters — Students explore what happens when a mirror is placed along different positions on shapes, digits, and words. They discover which digits from 0 to 9 have the same mirror image and find numbers like 181 and 686 that look identical in a mirror. Words written in mirror script (like those on an ambulance) are also discussed.
• Folding, Cutting, and Holes — The Holes and Cuts activity challenges students to predict where holes and cuts will appear when folded paper is opened. Three challenges involve folding paper once or twice, making cuts, and reasoning about the resulting shapes — building spatial thinking alongside symmetry understanding.
• Tiling and Floor Patterns — The chapter introduces tessellation through the Tiles section, where students identify repeating units and create patterns with no gaps or overlaps. The Catty Wall activity shows how a single cut-and-slide of a square tile can create an interlocking shape (like a cat's head) that still tiles perfectly. A nature walk project extends symmetry observation to leaves, petals, and butterflies.

1. 01The ink blot activity: fold paper, add colour drops, press — the result is a symmetrical pattern with a line of symmetry along the fold.
2. 02Paper aeroplane has multiple lines of symmetry; an asymmetrical plane flies differently (and usually worse).
3. 03The line dividing a shape into two equal halves is called the line of symmetry or mirror line / line of reflection.
4. 04Digits with the same mirror image include 0, 1, 8 — used to form mirror-image numbers like 181 and 686.
5. 05Ambulance writes words in mirror script so drivers see them correctly in a rear-view mirror.
6. 06Holes and Cuts challenges: fold paper once or twice, cut corners/sides, then predict the shape when opened.
7. 07Tiling activity uses sliding, flipping, and rotating of tile shapes to fill a surface with no gaps or overlaps.
8. 08Nature walk project: collect leaves and petals, categorise them as symmetrical or non-symmetrical, and make designs.