Chapter 1: Large Numbers Around Us
Part 1 — 20 Most Important 1-Mark Questions (with Solutions)
1How many zeros are there in one lakh?
One lakh is \(1,00,000\). It has 5 zeros.
2Write one lakh in the International (American) system using commas.
\(1,00,000\) (Indian) is \(100,000\) (International).
3What is the smallest 6-digit number called and how is it written?
It is called one lakh and written as \(1,00,000\).
4Write the number name of \(12,78,830\) in the Indian system.
Twelve lakh seventy eight thousand eight hundred thirty.
5How many lakhs make one crore?
\(1\,\text{crore} = 100\,\text{lakhs}\).
6Write \(1\,\text{crore}\) in numerals (Indian system).
\(1\,\text{crore} = 1,00,00,000\).
7Convert \(15,75,000\) to words (Indian system).
Fifteen lakh seventy five thousand.
8Fill in the blank: The largest 3-digit number is \(\_\_\_\_\).
\(999\).
9Fill in the blank: The smallest 4-digit number is \(\_\_\_\_\).
\(1000\).
10Write \(70,53,138\) in words (Indian system).
Seventy lakh fifty three thousand one hundred thirty eight.
11How many thousands make a lakh?
\(1\,\text{lakh} = 100 \times 1000\). So, 100 thousands make a lakh.
12Write \(3,00,600\) in words (Indian system).
Three lakh six hundred.
13Compare using <, > or =: \(30\,\text{thousand}\ \_\ \ 3\,\text{lakhs}\).
\(30,000 \lt 3,00,000\). So, \(30\,\text{thousand} \lt 3\,\text{lakhs}\).
14In the Indian system, how are commas placed?
From right: group as \(3\!-\!2\!-\!2\!-\!2\ldots\) (e.g., \(9,87,65,01,234\)).
15Write the International-style commas for \(9,87,65,01,234\).
It is \(9,876,501,234\) (International: billions/millions/thousands).
16Round \(76,068\) to the nearest thousand.
Nearest thousand is \(76,000\).
17Find the difference from a lakh: How much less is \(75,000\) than \(1,00,000\)?
\(1,00,000 - 75,000 = 25,000\).
18How many zeros are there in one billion (International)?
\(1\,\text{billion} = 1,000,000,000\) → 9 zeros. (Indian: \(= 100\,\text{crore} = 1\,\text{arab}\)).
19Quickly compute: \(25 \times 12 = \ ?\)
\(25 \times 12 = (25 \times 100)/8 = 300\).
20State whether the product of two 2-digit numbers can be a 5-digit number.
No. It will be a 3-digit or 4-digit number (since \(10 \times 10 = 100\) and \(99 \times 99 = 9801\)).
Chapter 1: Large Numbers Around Us
Part 2 — 20 Most Important 2-Mark Questions (with Solutions)
1Write \(4,05,0678\) in words in both Indian and International systems.
Indian: Forty lakh fifty thousand six hundred seventy eight.
International: Four hundred five thousand six hundred seventy eight.
2Express in Indian notation: One crore one lakh one thousand ten.
It is \(1,01,01,010\).
3How much more than one lakh is \(1,06,000\)?
\(1,06,000 - 1,00,000 = 6,000\). So it is 6,000 more.
4The population of Chintamani increased from \(75,000\) (2011) to \(1,06,000\) (2024). Find the increase.
\(1,06,000 - 75,000 = 31,000\). Increase = 31,000.
5Round \(4,63,128 + 4,19,682\) to the nearest lakh.
Sum = \(8,82,810\). Nearest lakh = \(8,83,000\).
6Round \(14,63,128 - 4,90,020\) to the nearest lakh.
Difference = \(9,73,108\). Nearest lakh = \(9,73,000\).
7How many thousands are required to make one crore?
\(1\,\text{crore} = 1,00,00,000 = 10,000 \times 1000\). So 10,000 thousands.
8Convert \(20022002\) into words (Indian system).
Two crore two lakh two thousand two.
9Compare and insert <, > or =: \(500\,\text{lakhs} \_\ 5\,\text{million}\).
\(500\,\text{lakhs} = 50,000,000\).
\(5\,\text{million} = 5,000,000\).
So \(500\,\text{lakhs} \gt 5\,\text{million}\).
10How many zeros are there in one crore?
\(1,00,00,000\). It has 7 zeros.
11If one person eats 2 varieties of rice daily, how many varieties can they taste in 100 years?
Days in 100 years \(= 365 \times 100 = 36,500\).
Varieties \(= 36,500 \times 2 = 73,000\).
12If each floor is 4 m high, how tall is a 20-floor building?
Height = \(20 \times 4 = 80\,\text{m}\).
13The Statue of Unity is 180 m tall. How many 20-floor buildings (80 m each) equal its height approximately?
\(180 \div 80 \approx 2.25\). So about 2 such buildings.
14Write the nearest crore to \(6,72,85,183\).
Nearest crore = \(7,00,00,000\).
15How many lakhs make a billion?
\(1\,\text{billion} = 1,000,000,000 = 1000 \times 1,00,000\).
So 10,000 lakhs.
16What is the product \(72 \times 125\) quickly? (Hint: \(125 = 1000/8\)).
\(72 \times 125 = (72 \times 1000)/8 = 9000\).
17Estimate whether \(4,63,128 + 4,19,682\) is closer to 8 lakh or 9 lakh.
Exact sum = \(8,82,810\). Closer to 9 lakh.
18Write the difference between International and Indian comma placement for the number \(246813579\).
Indian: \(24,68,13,579\). International: \(246,813,579\).
19If a bus carries 50 people, how many can 1 lakh buses carry?
Capacity = \(1,00,000 \times 50 = 50,00,000\) people.
20If one sheet of paper weighs 5 g, what will be the weight of 1 lakh sheets?
Weight = \(1,00,000 \times 5 = 5,00,000\) g = 500 kg.
Chapter 1: Large Numbers Around Us
Part 3 — 20 Most Important 3-Mark Questions (with Solutions)
1Write \(27,30,000\) in words (Indian system) and also in International system.
Indian: Twenty seven lakh thirty thousand.
International: Two million seven hundred thirty thousand.
2Find the population increase of Bengaluru from 2001 to 2011 using the table (43,01,326 to 84,25,970).
Increase = \(84,25,970 - 43,01,326 = 41,24,644\).
3Estimate the sum: \(14,63,128 - 4,90,020\). Then compare with exact answer.
Exact difference = \(9,73,108\).
Estimate ≈ \(15,00,000 - 5,00,000 = 10,00,000\).
Close to actual value, difference = 26,892 less.
4Write 3 different ways to express \(5072\) using Chitti’s calculator buttons.
(i) \((50 \times 100) + (7 \times 10) + (2 \times 1)\).
(ii) \((3 \times 1000) + (20 \times 100) + (72 \times 1)\).
(iii) \((5 \times 1000) + (0 \times 100) + (7 \times 10) + (2 \times 1)\).
5Compare: \(640\,\text{crore}\) and \(60\,\text{billion}\).
\(640\,\text{crore} = 6,40,00,00,000 = 6.4\,\text{billion}\).
So \(640\,\text{crore} \lt 60\,\text{billion}\).
6Convert: Ten crore twenty lakh thirty thousand forty into numeral form.
It is \(10,20,30,040\).
7If a person eats 3 varieties of rice daily, how many can they taste in 100 years?
Days in 100 years = \(365 \times 100 = 36,500\).
Varieties = \(36,500 \times 3 = 1,09,500\).
So, more than one lakh.
8Convert the number \(9876501234\) into Indian and International names.
Indian: \(9,87,65,01,234\) → 987 crore 65 lakh 1 thousand 234.
International: \(9,876,501,234\) → 9 billion 876 million 501 thousand 234.
9Write five nearest neighbours of \(3,87,69,957\).
Nearest thousand = \(3,87,70,000\).
Nearest ten thousand = \(3,87,70,000\).
Nearest lakh = \(3,87,70,000\).
Nearest ten lakh = \(3,90,00,000\).
Nearest crore = \(4,00,00,000\).
10If a whale weighs \(10,50,00,000 \div 700\) kg, find its weight.
Weight = \(15,000\) kg.
11A newborn whale weighs 2700 kg. Compare it with a hippopotamus (≈ 2700 kg).
Both have nearly equal weight ≈ 2.7 tonnes.
12If a bus carries 50 people, how many buses are needed to carry Mumbai’s 2011 population (1,24,42,373)?
Number of buses = \(1,24,42,373 \div 50 \approx 2,48,847\).
13If Roxie travels 100 km per day, how far in 10 years?
1 year = 365 days. Distance in 10 years = \(100 \times 365 \times 10 = 3,65,000\) km.
14Can Roxie reach the Moon (distance \(3,84,400\) km) in 10 years at 100 km/day?
She covers 3,65,000 km, which is slightly less than 3,84,400 km.
So she cannot fully reach, but very close.
15Find the product quickly: \(2 \times 1768 \times 50\).
\(= (2 \times 50) \times 1768 = 100 \times 1768 = 1,76,800\).
16Find the approximate distance covered per day by a bar-tailed godwit that flew 13,560 km in 11 days.
Average per day = \(13,560 \div 11 = 1233\) km/day.
17Find the number of digits in product of two 3-digit numbers.
Smallest product = \(100 \times 100 = 10,000\) (5-digit).
Largest product = \(999 \times 999 = 998001\) (6-digit).
So 5 or 6 digits.
18If one crore = 100 lakhs, find how many crores in one arab.
1 arab = 100 crores.
19If a coin is 1 mm thick, how many coins are needed to match 180 m (Statue of Unity)?
Height = \(180 \times 1000 = 1,80,000\) mm.
Coins = 1,80,000 coins.
20Divide: \(52,00,00,00,000 \div 130\). What fact does it reveal?
Quotient = 40,00,00,000 tonnes.
It represents global plastic waste generated in 2021.
Chapter 1: Large Numbers Around Us
Part 4 — NCERT Exercise Questions with Solutions
Ex 1.1 Q1According to Census 2011, Chintamani’s population was 75,000. How much less than one lakh is this?
\(1,00,000 - 75,000 = 25,000\).
So, 25,000 less.
Ex 1.1 Q2In 2024, population = 1,06,000. How much more than one lakh?
\(1,06,000 - 1,00,000 = 6,000\).
So, 6,000 more.
Ex 1.1 Q3By how much did the population increase from 2011 to 2024?
Increase = \(1,06,000 - 75,000 = 31,000\).
Ex 1.2 Q1Thoughtful Thousands calculator: How many times to press +1000 to show (a) 10,000 (b) 53,000 (c) 90,000 (d) 1 lakh?
(a) 10 times.
(b) 53 times.
(c) 90 times.
(d) 100 times.
Ex 1.2 Q2Tedious Tens calculator: How many times to press +10 to show (a) 500 (b) 780 (c) 1000 (d) 3700 (e) 10,000 (f) 1 lakh?
(a) 50 times.
(b) 78 times.
(c) 100 times.
(d) 370 times.
(e) 1000 times.
(f) 10,000 times.
Ex 1.2 Q3Handy Hundreds calculator: How many +100 presses for (a) 400 (b) 3700 (c) 10,000 (d) 53,000 (e) 90,000 (f) 97,600 (g) 1,00,000?
(a) 4 times.
(b) 37 times.
(c) 100 times.
(d) 530 times.
(e) 900 times.
(f) 976 times.
(g) 1000 times.
Ex 1.3 Q1Read the following numbers in Indian system and also give International names: (a) 4050678 (b) 48121620 (c) 20022002 (d) 246813579.
(a) Indian: Forty lakh fifty thousand six hundred seventy eight. International: Four million fifty thousand six hundred seventy eight.
(b) Indian: Four crore eighty one lakh twenty one thousand six hundred twenty. International: Forty eight million one hundred twenty one thousand six hundred twenty.
(c) Indian: Two crore two lakh two thousand two. International: Twenty million twenty two thousand two.
(d) Indian: Twenty four crore sixty eight lakh thirteen thousand five hundred seventy nine. International: Two hundred forty six million eight hundred thirteen thousand five hundred seventy nine.
(b) Indian: Four crore eighty one lakh twenty one thousand six hundred twenty. International: Forty eight million one hundred twenty one thousand six hundred twenty.
(c) Indian: Two crore two lakh two thousand two. International: Twenty million twenty two thousand two.
(d) Indian: Twenty four crore sixty eight lakh thirteen thousand five hundred seventy nine. International: Two hundred forty six million eight hundred thirteen thousand five hundred seventy nine.
Ex 1.3 Q2Write in Indian notation: (a) One crore one lakh one thousand ten (b) One billion one million one thousand one (c) Ten crore twenty lakh thirty thousand forty.
(a) \(1,01,01,010\).
(b) One billion one million one thousand one = \(1,001,001,001\) (International). In Indian commas: \(100,10,01,001\).
(c) \(10,20,30,040\).
Ex 1.3 Q3Compare: (a) 30 thousand ___ 3 lakhs (b) 500 lakhs ___ 5 million (c) 800 thousand ___ 8 million (d) 640 crore ___ 60 billion.
(a) \(30,000 \lt 3,00,000\).
(b) \(500 \,\text{lakhs} = 50,000,000 \gt 5,000,000\).
(c) \(800,000 \lt 8,000,000\).
(d) \(640\,\text{crore} = 6.4\,\text{billion} \lt 60\,\text{billion}\).
Ex 1.4 Q1Exact value of \(4,63,128 + 4,19,682\)? Estimate greater than 8,50,000 or less?
Exact = \(8,82,810\). It is greater than 8,50,000.
Ex 1.4 Q2Exact value of \(14,63,128 - 4,90,020\)? Estimate greater than 9,50,000 or less?
Exact = \(9,73,108\). Greater than 9,50,000.
Ex 1.5 Q1Find quick products: (a) \(2 \times 1768 \times 50\) (b) \(72 \times 125\) (c) \(125 \times 40 \times 8 \times 25\).
(a) \(1,76,800\).
(b) \(9,000\).
(c) \(1,00,000\).
Ex 1.5 Q2Calculate quickly: (a) 25 × 12 (b) 25 × 240 (c) 250 × 120 (d) 2500 × 12.
(a) 300. (b) 6000. (c) 30,000. (d) 30,000.
Ex 1.6 Q1If one bus carries 50, how many can 1 lakh buses carry? Can they fit Mumbai population (1.24 crore)?
Capacity = 50,00,000. Population = 1,24,00,000+.
So, No, they cannot fit.
Ex 1.6 Q2If Roxie travels 100 km/day, distance in 10 years? Can she reach Moon (3,84,400 km)?
Distance = \(100 \times 365 \times 10 = 3,65,000\) km.
Moon distance = 3,84,400 km.
She cannot fully reach, but nearly.