Mirror Pencil
Reflect endpoints first, keeping their distance from the mirror equal, then connect them. A reflected slant reverses direction.
Before you try
Before you play, make a prediction: Which distance stays equal in reflection? Explain what you expect and what part of the model will help you check it.
Try it out
Interactive activity
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What happened?
Move a control to see what changes and why.
The game practises one idea at a time with simple drawn pictures. Check the same idea with real objects and your NCERT textbook (Chapter 11: Fun with Symmetry, pages 164–174).
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Try these ideas
- Complete the outline across the dashed mirror.
- Try a new puzzle with ↻. Describe what changed and which mathematical rule stayed the same.
- Complete a round, then explain your method before you move to the next one.
Why it works
Reflect endpoints first, keeping their distance from the mirror equal, then connect them. A reflected slant reverses direction.
Reflecting (two steps left, one step up) puts it two steps right, one step up. Complete the outline across the dashed mirror.
Reflect both endpoints. Copying the same slant can produce a translated line instead.
This activity connects to Fun with Symmetry, NCERT Class 4 maths, printed pages 164–174. Use the picture or objects to explain each step before relying on a calculation. The game practises one part of the chapter at a time; the other three activities extend the chapter’s ideas.
Worked example: Complete a slanting line across a vertical mirror. Reflect each endpoint to the opposite side at the same distance. Join the reflected endpoints. The slant reverses, making the matching other half.
Check your understanding
Question 1 of 2
Which distance stays equal in reflection?
Does a non-square rectangle have diagonal symmetry lines?
Explain it in your own words
What changed? Why did it happen? Where might you notice this in everyday life?
For parents & teachers
- Try with everyday materials. Complete the outline across the dashed mirror. Ask the child to make a new example using paper, counters, household objects or a labelled sketch.
- Listen to the explanation. Reflect both endpoints. Copying the same slant can produce a translated line instead. Ask “How could we check?” and encourage a second representation of the same idea.