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NCERT Solutions Ganita Prakash (Part 1) Chapter 1 –91.3 Of Crores and Crores! — In-text Questions

Book page 8 Updated on2026-09-05

Q1.
What if we press the +10,00,000 button ten times? What number will come up? How many zeroes will it have? What should we call it?
Answer

You get 1,00,00,000 — one crore — and it has 7 zeroes.

10,00,000 × 10
= 1,00,00,000
= 100 lakhs = 1 crore
1 followed by 7 zeroes
Why it happens: Multiplying by 10 pushes every digit one place to the left and adds a zero at the end. Ten lakh already has 6 zeroes, so ten times that has 7.
Tip: Keep a ladder in your head — 1 lakh (5 zeroes) → 10 lakh (6) → 1 crore (7) → 10 crore (8) → 1 arab (9).
Q2.
How many zeros does a thousand lakh have? _____
Answer

8 zeroes.

1 thousand lakh = 1,000 × 1,00,000
= 1,000 × 100,000
= 10,00,00,000
= 10 crore
Zeroes: 3 (from 1,000) + 5 (from 1 lakh) = 8
Why it happens: When you multiply two numbers that are each 1 followed by zeroes, the zeroes simply add up. 103 × 105 = 108.
Q3.
How many zeros does a hundred thousand have? ____
Answer

5 zeroes.

1 hundred thousand = 100 × 1,000
= 1,00,000
Zeroes: 2 + 3 = 5
And 1,00,000 = 1 lakh
Why it happens: This is the bridge between the two systems. What the American system calls “one hundred thousand” (written 100,000) the Indian system calls “one lakh” (written 1,00,000) — same number, different commas and a different name.
Did you know? The word lakh comes from the Sanskrit lakṣha and crore from koṭi. The Indian system is also used in Nepal, Sri Lanka, Bangladesh, Pakistan, Bhutan, Maldives, Afghanistan and Myanmar.
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