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NCERT Solutions Poorvi Chapter 3 My Brother's Great Invention (story by Anita Rau Badami) — Let us do these activities before we read

Book page 91 Updated on2026-09-05

Q1.
I Work in pairs and guess the invention. 1. I am a concept invented by ancient Indian mathematicians. I add value to numbers. Without me, calculations in the modern digital world would be impossible. Who am I?
Answer

Zero (shunya, 0).

I am a concept invented by ancient Indian mathematicians → zero
I add value to numbers → 5 becomes 50, then 500
Without me, digital calculation is impossible → computers work on 0 and 1
Why it happens: Indian mathematicians were the first to treat zero as a number and not merely as an empty space. Aryabhata used a place-value system that needs zero, and Brahmagupta (628 CE) wrote the first rules for calculating with zero in the Brahmasphutasiddhanta. Without a symbol for 'nothing', the place value of a digit cannot be fixed — and every computer, which stores everything as strings of 0 and 1, would be impossible.
Did you know? The word shunya travelled to Arabic as sifr, and from there into English as both 'cipher' and 'zero'.
Q2.
I 2. I am an ancient Indian practice, now popular globally. I focus on physical and mental well-being. What am I?
Answer

Yoga.

Why it happens: Yoga is thousands of years old in India and was set down systematically by Patanjali in the Yoga Sutras. It joins asanas (postures), pranayama (breath control) and dhyana (meditation), so it works on the body and the mind together — exactly what the clue means by 'physical and mental well-being'.
Did you know? The United Nations declared 21 June as the International Day of Yoga in 2014, on India's proposal. It is now observed in more than 190 countries.
Q3.
II Discuss in groups of four what you think the world today would have been like without inventions and discoveries.
Answer

Take one area each in your group — home, travel, health, school, communication — and say what that area would look like if the key invention had never happened. Then put the four pictures together.

Sample answer: Without inventions, life would be slower, shorter and much smaller. Without the wheel and the engine we would still walk to the next village, so most people would never travel more than twenty kilometres from home. Without electricity there would be no fan, no fridge, no light after sunset — the day would end at dusk. Without vaccines and antibiotics an ordinary fever could kill, and without printing and the internet, learning would pass only by word of mouth, so a discovery made in Kerala would take a lifetime to reach Kashmir. But we should also remember the other side: inventions have brought pollution, plastic and screen addiction. So the real question is not 'inventions or no inventions' but which inventions we choose and how wisely we use them.

Tip: In a group discussion, begin with 'I agree with… and I would add that…' instead of interrupting. Give each speaker one minute.
Q4.
III Fill the grid given below with missing letters to complete the words. These words display qualities of an inventor.
Answer

The five words are the five qualities of an inventor:

RowGrid as printedComplete wordWhat the quality means
1C R _ A T _ V _ T _CREATIVITYThe power to think of something new
2C U _ _ _ _ I T YCURIOSITYThe wish to know how and why things work
3R I _ _ - T _ K _ N GRISK-TAKINGThe courage to try when you may fail
4D E T E _ _ I N A T I _ _DETERMINATIONRefusing to give up after a failure
5I _ _ G I _ A _ I O NIMAGINATIONSeeing in the mind what does not yet exist
Why it happens: Anand in this story has every one of the five. He is curious about how a door can be made to warn you, creative enough to design a burglar alarm, a risk-taker who tries it on his own front door, determined enough to start a time machine a week after being scolded, and imaginative enough to believe a thief walked into the past.
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