## The Mysterious Parcel

### Topic: Rotational Symmetry

Mr Postman is at the door with a parcel. “A parcel? I do not receive any parcels usually. This is so strange”, thinks Triho. What might the parcel have? What if it has something dangerous? Oh no! Let us find out.

Curious to find out what the parcel holds, Triho quickly opens it. “What? Some broken pieces? Why would someone send such pieces to me?” he thinks. Unable to understand, he decides to call Uncle Math and seek his help.

He calls Uncle Math and explains everything. Uncle Math immediately decides to come over.

“Hmm! This is weird! What if this means something? I think the broken pieces need to join together to unravel the mystery”, says Uncle Math looking at the parcel. Soon they start examining the pieces while keeping them in various patterns.

“I think we are not placing them right”, says Uncle Math. Together they try even harder to solve this mystery. Suddenly Triho turns the pieces here and there and joins them together as if he is joining the puzzle pieces.

Voila! It works! The pieces together form a square shape. He is elated. Uncle Math is impressed too.

But soon they observe that the square puzzle has some figures indicated on it. Now, happy Uncle Math turns into sad Uncle Math. But why? What do the figures on the pieces indicate?

Unable to grasp the severity of this, Triho continues playing with the puzzle, rotating, flipping it here and there. Suddenly, he notices something and is all excited. “Hey, Uncle Math! Look the figures on the puzzle look the same even when I rotate it in any direction. Amazing right?” he says.

“Yes! These shapes have rotational symmetry”, says Uncle Math in a low tone. “Eh? What does that mean?” questions Triho. “If a figure is rotated around a centre point and it still appears exactly as it did before the rotation, it is said to have rotational symmetry”, explains Uncle Math. Triho still looks clueless.

Uncle Math takes a pen and draws two points on the first shape, one in the centre and one in the corner. Pointing at the centre point, Uncle Math says, “I will rotate this figure on this point”, and then he points at the corner and says, “This will be our reference point. So when I rotate this figure, you can easily spot if it is still the same”.

“Alright, here we go. Observe the reference point carefully”, says Uncle Math and rotates the figure from its centre point for one turn. “Did the figure fit into its original outline even when rotated?” he questions. “Oh yes! It did thrice”, answers Triho.

“Exactly. This means that the figure has rotational symmetry and its order is 3. Order of rotational symmetry is the number of times a shape fits into its original outline when it is rotated a full turn”, explains Uncle Math. Triho is now able to understand.

Triho rotates the puzzle himself to check if the new figure has rotational symmetry or not. “Oh yes! It has rotational symmetry of order 4”, he says. Uncle Math agrees with him. “But what do these figures mean? Do they indicate someplace in the galaxy?” he asks.

“Yes! These are the prominent places from the Rotational Symmetry Land! Why are these sent to us? Who must have sent this parcel? Oh no! Is the land safe?” says Uncle Math anxiously. Triho is tensed too.

“I am sure this is sent by Uncle Bad! May be, he is planning the next attack on Rotational Symmetry Land!” guesses Triho looking at the figures carefully. Uncle Math still wants to understand his rationale behind saying this. “Triho flips the puzzle, look here, there is a target icon in the centre of the puzzle! Only Uncle Bad uses such icons. He is playing with us”, adds Triho.

Now, Uncle Math is sure too! “What do we do? He must have already reached there. How do we save the land?” questions Triho. This is a tough situation. What do you think should they do to save the land from the attack?

Uncle Math and Triho decide to go there and fight Uncle Bad. Hopefully, things will be alright soon.

“Oh, you are here already! So you could solve the puzzle, nice!” says Uncle Bad as he waits on the land with his army. “Yes! But will you use your whole army to fight against the two of us? Haha! Funny!” mocks Triho to provoke him. Is this Triho’s new tactic?

“I am Uncle Bad! I make everyone sad! I do not need anybody’s help to fight! Let us have a one-on-one battle. Whoever wins will stay here and the loser will leave immediately to never return. Deal?” says Uncle Bad. Triho’s tactic has worked and Uncle Math decides to fight Uncle Bad.

Crash! Bam! Boom! Pop! The fight goes on for a while. None of them is ready to give up. Uncle Math has the power of his genius brain. Uncle Bad has the power of evil. Who will win?

“Yayy! It looks like Uncle Math is going to win”, says Triho to himself. Uncle Bad is surprised to see his opponent being so strong. Will he continues the fight? Who will win the Rotational Symmetry Land?

Finally, Uncle Math decides to try something tricky. He immediately starts running fast towards a triangular wall. Uncle Bad doesn’t understand this move. Before he could counter him, Uncle Math jumps on him from the top of the triangular wall.

Uncle Bad gets badly injured. He decides to run away this time. “I will remember this! You will be punished! Get ready for a stronger attack!” he says and leaves.

Hurrah! Uncle Math has won! This proves that intelligence is the most powerful weapon and can even beat strength. Both of them are elated.

A strange parcel, tricky puzzle, rotational symmetry, and a tough fight, all teach us that however difficult the situation is it can be tackled with patience and intelligence. Do you agree?

### We Learnt That…

• If a figure is rotated around a centre point and it still appears exactly as it did before the rotation, it is said to have rotational symmetry.
• Order of rotational symmetry is the number of times a shape fits into its original outline when it is rotated at a full turn.
• Not just shapes, even some letters, and numbers have rotational symmetry.

### Let’s Discuss!

• Why was I surprised?
• What did the parcel have? Who had sent it?
• How did we solve the puzzle?
• What is rotational symmetry? Explain.
• Can you identify the alphabets and numbers that have rotational symmetry?