Class 7 : Maths โ Lesson 1. Large Numbers Around Us
EXPLANATION AND ANALYSIS
๐ต Introduction: Large Numbers in Everyday Life
๐ง In our daily activities, we usually deal with small numbers such as the number of books, students, or money spent on simple items. However, there are many situations around us where numbers become very large. Such numbers appear when we read newspapers, watch news, or study subjects like science and geography.
๐ฟ Examples from daily life
๐ต Population of a country is counted in crores
๐ข Distance between planets is measured in thousands or lakhs of kilometres
๐ก Government budgets involve very large numbers
๐ด Digital data is measured in gigabytes and terabytes
โก๏ธ To understand these facts clearly, we must learn how to read, write, compare, and estimate large numbers correctly. This chapter introduces these ideas.
๐ข Place Value: The Basis of Large Numbers
๐ง Every digit in a number has a value depending on its position. This is called the place value of the digit.
๐ Example
In the number 4,36,728, the digit 3 represents 30,000.
๐ก Concept:
Each place to the left has a value ten times greater than the place to its right.
๐ต Indian Place Value System
๐ง In India, we follow the Indian place value system.
๐ต Ones
๐ข Tens
๐ก Hundreds
๐ด Thousands
๐ต Lakhs
๐ข Crores
๐ Example
The number 6,48,25,309 is read as
Six crore forty-eight lakh twenty-five thousand three hundred nine
โ๏ธ Note:
In the Indian system, commas are placed after the first three digits from the right and then after every two digits.
๐ข International Place Value System
๐ Many other countries use the International place value system.
๐ต Ones
๐ข Tens
๐ก Hundreds
๐ด Thousands
๐ต Millions
๐ข Billions
๐ Example
The number 64,825,309 is read as
Sixty-four million eight hundred twenty-five thousand three hundred nine
๐ก Concept:
Indian system uses lakh and crore, while International system uses million and billion.
๐ก Reading Large Numbers
๐ง To read large numbers correctly, we should follow a fixed method.
๐ต Place commas correctly
๐ข Start reading from the leftmost group
๐ก Use correct place value names
๐ Example
5,03,07,418 is read as
Five crore three lakh seven thousand four hundred eighteen
๐ด Common mistake:
Reading digits one by one instead of using place values.
๐ต Writing Large Numbers in Numerals
๐ง While writing numbers given in words, it is important to identify place value words like thousand, lakh, and crore.
๐ Example
Seven crore four lakh two thousand sixty-five
7,04,02,065
โ๏ธ Note:
Zeros are very important in large numbers. Missing a zero changes the value of the number.
๐ข Comparing Large Numbers
๐ง Large numbers can be compared easily by following a fixed order.
๐ต Step 1: Compare the number of digits
๐ข Step 2: If digits are equal, compare digits from the left
๐ก Step 3: The number with the greater digit is larger
๐ Example
Compare 8,34,912 and 8,29,745
Both have six digits
At the ten-thousands place, 3 is greater than 2
So 8,34,912 is greater
๐ก Ordering Large Numbers
๐ง Ordering means arranging numbers in a particular sequence.
๐ต Ascending order means smallest to greatest
๐ข Descending order means greatest to smallest
๐ Example
2,84,679, 2,96,540, 3,10,428 in ascending order
2,84,679 < 2,96,540 < 3,10,428
๐ต Estimation and Rounding Off
๐ง Estimation gives an approximate value of a number when an exact value is not required.
๐ต Look at the digit to the right
๐ข If it is less than 5, round down
๐ก If it is 5 or more, round up
๐ Example
Round 6,72,418 to the nearest thousand
The hundreds digit is 4
The rounded value is 6,72,000
๐ก Concept:
Estimation makes calculations quicker and easier.
๐ข Use of Large Numbers in Daily Life
๐ฟ Large numbers are used in many fields.
๐ต Population studies
๐ข Space science
๐ก Banking and finance
๐ด Government planning
๐ต Digital storage
๐ Example
The distance between Earth and the Moon is about 3,84,400 kilometres.
๐ด Common Errors to Avoid
๐ด Wrong placement of commas
๐ด Mixing Indian and International systems
๐ด Forgetting zeros
๐ด Incorrect reading of place values
โ๏ธ Note:
Always recheck comma placement before reading or writing a number.
๐ข Importance of Learning Large Numbers
๐ง Understanding large numbers helps us interpret real-world data correctly.
๐ต Builds strong number sense
๐ข Helps in science and geography
๐ก Useful for higher mathematics
๐ด Important for everyday understanding
๐ Summary
๐ต Large numbers help us describe very big quantities
๐ข Place value gives meaning to each digit
๐ก Indian and International systems are different
๐ด Correct reading and writing depend on comma placement
๐ต Numbers can be compared and ordered easily
๐ข Estimation gives approximate values
๐ก Large numbers are used widely in daily life
๐ Quick Recap
๐ Quick Recap
๐ต Large numbers represent huge quantities
๐ข Place value decides digit value
๐ก Indian system uses lakh and crore
๐ด International system uses million and billion
๐ต Estimation simplifies calculations
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TEXTBOOK QUESTIONS
๐ฟ 1.1 A LAKH VARIETIES!
๐ โ Question 1.
According to the 2011 Census, the population of the town of Chintamani was about 75,000. How much less than one lakh is 75,000?
๐ โ
Answer:
๐น One lakh = 1,00,000
๐น Given population = 75,000
๐น Difference = 1,00,000 โ 75,000
๐ธ = 25,000
โ๏ธ Final: 75,000 is 25,000 less than one lakh.
๐ โ Question 2.
The estimated population of Chintamani in the year 2024 is 1,06,000. How much more than one lakh is 1,06,000?
๐ โ
Answer:
๐น One lakh = 1,00,000
๐น Estimated population = 1,06,000
๐น Difference = 1,06,000 โ 1,00,000
๐ธ = 6,000
โ๏ธ Final: 1,06,000 is 6,000 more than one lakh.
๐ โ Question 3.
By how much did the population of Chintamani increase from 2011 to 2024?
๐ โ
Answer:
๐น Population in 2011 = 75,000
๐น Population in 2024 = 1,06,000
๐น Increase = 1,06,000 โ 75,000
๐ธ = 31,000
โ๏ธ Final: The population increased by 31,000 from 2011 to 2024.
๐ฟ 1.2 LAND OF TENS
๐ โ Figure it Out (a)
For the number 8300, write expressions for at least two different ways to obtain the number through button clicks.
๐ โ
Answer:
๐น Way 1: (83 ร 100) = 8300
๐น Way 2: (8 ร 1000) + (3 ร 100) = 8300
๐ โ Figure it Out (b)
For the number 40629, write expressions for at least two different ways to obtain the number through button clicks.
๐ โ
Answer:
๐น Way 1: (40 ร 1000) + (6 ร 100) + (2 ร 10) + (9 ร 1) = 40629
๐น Way 2: (4 ร 10000) + (62 ร 10) + (9 ร 1) = 40629
๐ โ Figure it Out (c)
For the number 56354, write expressions for at least two different ways to obtain the number through button clicks.
๐ โ
Answer:
๐น Way 1: (56 ร 1000) + (3 ร 100) + (5 ร 10) + (4 ร 1) = 56354
๐น Way 2: (5 ร 10000) + (63 ร 100) + (5 ร 10) + (4 ร 1) = 56354
๐ โ Figure it Out (d)
For the number 66666, write expressions for at least two different ways to obtain the number through button clicks.
๐ โ
Answer:
๐น Way 1: (6 ร 10000) + (6 ร 1000) + (6 ร 100) + (6 ร 10) + (6 ร 1) = 66666
๐น Way 2: (66 ร 1000) + (6 ร 100) + (6 ร 10) + (6 ร 1) = 66666
๐ โ Figure it Out (e)
For the number 367813, write expressions for at least two different ways to obtain the number through button clicks.
๐ โ
Answer:
๐น Way 1: (3 ร 100000) + (6 ร 10000) + (7 ร 1000) + (8 ร 100) + (1 ร 10) + (3 ร 1) = 367813
๐น Way 2: (367 ร 1000) + (8 ร 100) + (1 ร 10) + (3 ร 1) = 367813
๐ โ Question 1.
For the numbers in the previous exercise, find out how to get each number by making the smallest number of button clicks and write the expression.
๐ โ
Answer:
๐น 8300
๐ธ (8 ร 1000) + (3 ร 100) = 8300
๐น 40629
๐ธ (4 ร 10000) + (0 ร 1000) + (6 ร 100) + (2 ร 10) + (9 ร 1) = 40629
๐น 56354
๐ธ (5 ร 10000) + (6 ร 1000) + (3 ร 100) + (5 ร 10) + (4 ร 1) = 56354
๐น 66666
๐ธ (6 ร 10000) + (6 ร 1000) + (6 ร 100) + (6 ร 10) + (6 ร 1) = 66666
๐น 367813
๐ธ (3 ร 100000) + (6 ร 10000) + (7 ร 1000) + (8 ร 100) + (1 ร 10) + (3 ร 1) = 367813
๐ โ Question 2.
Do you see any connection between each number and the corresponding smallest number of button clicks?
๐ โ
Answer:
๐น The smallest number of button clicks is obtained by using the place value of each digit.
๐น Each digit tells how many times a particular place-value button is pressed.
๐น This avoids unnecessary extra button presses and gives the minimum total clicks.
๐ โ Question 3.
If you notice, the expressions for the least button clicks also give the Indian place value notation of the numbers. Think about why this is so.
๐ โ
Answer:
๐น Indian place value notation breaks a number into digits multiplied by their place values.
๐น Creative Chittiโs buttons exactly match these place values (+1, +10, +100, +1000, โฆ).
๐น Therefore, using the least button clicks naturally follows the Indian place value system.
๐ฟ 1.3 OF CRORES AND CRORES!
๐ โ Question 1.
Read the following numbers in Indian place value notation and write their number names in both the Indian and American systems.
๐ โ
Answer:
๐น (a) 4050678
๐ธ Indian system: Forty lakh fifty thousand six hundred seventy eight
๐ธ American system: Four million fifty thousand six hundred seventy eight
๐น (b) 48121620
๐ธ Indian system: Four crore eighty one lakh twenty one thousand six hundred twenty
๐ธ American system: Forty eight million one hundred twenty one thousand six hundred twenty
๐น (c) 20022002
๐ธ Indian system: Two crore two thousand two
๐ธ American system: Twenty million twenty two thousand two
๐น (d) 246813579
๐ธ Indian system: Twenty four crore sixty eight lakh thirteen thousand five hundred seventy nine
๐ธ American system: Two hundred forty six million eight hundred thirteen thousand five hundred seventy nine
๐น (e) 345000543
๐ธ Indian system: Thirty four crore fifty lakh five hundred forty three
๐ธ American system: Three hundred forty five million five hundred forty three
๐น (f) 1020304050
๐ธ Indian system: One hundred two crore three lakh four thousand fifty
๐ธ American system: One billion twenty million three hundred four thousand fifty
๐ โ Question 2.
Write the following numbers in Indian place value notation.
๐ โ
Answer:
๐น (a) One crore one lakh one thousand ten
๐ธ 1,01,01,010
๐น (b) One billion one million one thousand one
๐ธ 1,00,10,01,001
๐น (c) Ten crore twenty lakh thirty thousand forty
๐ธ 10,20,30,040
๐น (d) Nine billion eighty million seven hundred thousand six hundred
๐ธ 90,80,07,00,600
๐ โ Question 3.
Compare and write โ<โ, โ>โ or โ=โ.
๐ โ
Answer:
๐น (a) 30 thousand < 3 lakhs
๐น (b) 500 lakhs = 5 million
๐น (c) 800 thousand < 8 million
๐น (d) 640 crore > 60 billion
๐ฟ 1.5 PATTERNS IN PRODUCTS
๐ โ Figure it Out โ Question 1
Find quick ways to calculate these products.
๐ โ
Answer:
๐น (a) 2 ร 1768 ร 50
๐ธ (2 ร 50) ร 1768 = 100 ร 1768 = 176800
๐น (b) 72 ร 125
๐ธ 125 = 1000 / 8
๐ธ 72 ร (1000 / 8) = 9 ร 1000 = 9000
๐น (c) 125 ร 40 ร 8 ร 25
๐ธ (125 ร 8) ร (40 ร 25)
๐ธ 1000 ร 1000 = 1000000
๐ โ Figure it Out โ Question 2
Calculate these products quickly.
๐ โ
Answer:
๐น (a) 25 ร 12
๐ธ (100 / 4) ร 12 = 300
โ๏ธ Final: 300
๐น (b) 25 ร 240
๐ธ (100 / 4) ร 240 = 6000
โ๏ธ Final: 6000
๐น (c) 250 ร 120
๐ธ (1000 / 4) ร 120 = 30000
โ๏ธ Final: 30000
๐น (d) 2500 ร 12
๐ธ (10000 / 4) ร 12 = 30000
โ๏ธ Final: 30000
๐น (e) _____ ร _____ = 12000000
๐ธ 12000 ร 1000 = 12000000
๐ฟ 1.6 DID YOU EVER WONDER…?
๐ โ Question 1
Using all digits from 0โ9 exactly once (the first digit cannot be 0) to create a 10-digit number, write theโ
(a) Largest multiple of 5
(b) Smallest even number
๐ โ Answer:
๐น (a) Largest multiple of 5
๐ธ A multiple of 5 must end in 0 or 5.
๐ธ To make the number largest, place the largest digits in the highest places.
๐ธ Ending with 0 gives a larger number than ending with 5.
๐ธ Arrange remaining digits from 9 to 1 in descending order.
โ๏ธ Final: 9876543210
๐น (b) Smallest even number
Smallest even number
๐ โ
Answer:
๐น The number must use digits 0โ9 exactly once, and the first digit cannot be 0.
๐น To make it smallest, keep the smallest digits as early as possible: start with 1, then 0, then 2, 3, 4, 5, 6, 7.
๐น The last digit must be even, so place 8 at the end and keep 9 just before it.
๐ โ Final: 1023456798
๐ โ Question 2
The number 10,30,285 in words is Ten lakhs thirty thousand two hundred eighty five, which has 43 letters. Give a 7-digit number name which has the maximum number of letters.
๐ โ Answer:
๐น Comparing long 7-digit number names shows that the word โseventyโ (7 letters) repeated many times gives more letters than โninetyโ (6 letters).
๐น The number 7,777,777 uses seventy and seven repeatedly along with lakh, thousand, and hundred, making its name very long.
๐น In words (Indian system):
Seventy seven lakh seventy seven thousand seven hundred seventy seven
๐ โ Final: 7,777,777
๐ โ Question 3
Write a 9-digit number where exchanging any two digits results in a bigger number. How many such numbers exist?
๐ โ Answer:
๐น For the number to increase after any exchange, the original number must be:
๐ธ Arranged in strictly increasing order from left to right.
๐น Smallest digits on the left, largest on the right.
๐น Example:
๐ธ 123456789
๐น Any swap will move a larger digit to a higher place value, making the number larger.
๐น Count of such numbers:
๐ธ Only one such arrangement is possible using digits 1โ9 once.
โ๏ธ Final:
๐น Number: 123456789
๐น Total such numbers: 1
๐ โ Question 4
Strike out 10 digits from the number 12345123451234512345 so that the remaining number is as large as possible.
๐ โ
Answer:
๐น We must delete 10 digits and keep 10 digits in the same order (a subsequence).
๐น To maximize the remaining 10-digit number, keep the earliest possible high digits (5s), while still leaving enough digits to complete 10 places.
๐น The largest possible remaining 10-digit number is obtained by keeping digits that form:
๐ โ Final: 5534512345
๐ โ Question 5
The words โzeroโ and โoneโ share letters โeโ and โoโ. The words โoneโ and โtwoโ share a letter โoโ, and the words โtwoโ and โthreeโ also share a letter โtโ. How far do you have to count to find two consecutive numbers which do not share an English letter in common?
๐ โ
Answer:
๐น Checking consecutive number-names in standard English spelling shows that every consecutive pair shares at least one common letter.
๐น This overlap continues because the same letters keep recurring in number words across ones, tens, hundreds, thousands, etc.
โ๏ธ Final: You cannot find such a pair of consecutive numbers (so there is no finite counting point where this happens).
๐ โ Question 6
Suppose you write down all the numbers 1, 2, 3, 4, …, 9, 10, 11, …
The tenth digit you write is โ1โ and the eleventh digit is โ0โ, as part of the number 10.
(a) What would the 1000th digit be? At which number would it occur?
(b) What number would contain the millionth digit?
(c) When would you have written the digit โ5โ for the 5000th time?
๐ โ Answer:
๐น (a) 1000th digit
๐ธ Digits from 1 to 9 = 9
๐ธ Digits from 10 to 99 = 90 ร 2 = 180
๐ธ Total digits up to 99 = 9 + 180 = 189
๐ธ Position inside 3-digit numbers = 1000 โ 189 = 811
๐ธ Each 3-digit number gives 3 digits
๐ธ Number offset = (811 โ 1) รท 3 = 270
๐ธ Digit position inside the number = (811 โ 1) mod 3 = 0 (first digit)
๐ธ Number = 100 + 270 = 370
๐ธ First digit of 370 = 3
โ๏ธ Final: 1000th digit is 3, and it occurs in the number 370
๐น (b) millionth digit
๐ธ Digits up to 9 = 9
๐ธ Digits from 10 to 99 = 180
๐ธ Digits from 100 to 999 = 900 ร 3 = 2700
๐ธ Total up to 999 = 9 + 180 + 2700 = 2889
๐ธ Digits from 1000 to 9999 = 9000 ร 4 = 36000
๐ธ Total up to 9999 = 2889 + 36000 = 38889
๐ธ Digits from 10000 to 99999 = 90000 ร 5 = 450000
๐ธ Total up to 99999 = 38889 + 450000 = 488889
๐ธ Millionth position inside 6-digit numbers = 1000000 โ 488889 = 511111
๐ธ Each 6-digit number gives 6 digits
๐ธ Number offset = (511111 โ 1) รท 6 = 85185
๐ธ Number = 100000 + 85185 = 185185
โ๏ธ Final: The millionth digit is contained in the number 185185
๐น (c) digit โ5โ for the 5000th time
๐ โ
Answer:
๐น Count of digit โ5โ written from 1 up to 13494 is 4999.
๐น The next number 13495 adds one more โ5โ, making the total 5000.
โ๏ธ Final: The digit โ5โ is written for the 5000th time while writing the number 13495.
๐ โ Question 7
A calculator has only โ+10,000โ and โ+100โ buttons. Write an expression describing the number of button clicks to be made for the following numbers:
(a) 20,800
(b) 92,100
(c) 1,20,500
(d) 65,30,000
(e) 70,25,700
๐ โ Answer:
๐น (a) 20,800
๐ธ 2 ร 10,000 = 20,000
๐ธ 8 ร 100 = 800
๐ธ 20,000 + 800 = 20,800
๐ โ
Final: 2 clicks of +10,000 and 8 clicks of +100
๐น (b) 92,100
๐ธ 9 ร 10,000 = 90,000
๐ธ 21 ร 100 = 2,100
๐ธ 90,000 + 2,100 = 92,100
๐ โ
Final: 9 clicks of +10,000 and 21 clicks of +100
๐น (c) 1,20,500
๐ธ 12 ร 10,000 = 1,20,000
๐ธ 5 ร 100 = 500
๐ธ 1,20,000 + 500 = 1,20,500
๐ โ
Final: 12 clicks of +10,000 and 5 clicks of +100
๐น (d) 65,30,000
๐ธ 653 ร 10,000 = 65,30,000
๐ โ
Final: 653 clicks of +10,000 and 0 clicks of +100
๐น (e) 70,25,700
๐ธ 702 ร 10,000 = 70,20,000
๐ธ 57 ร 100 = 5,700
๐ธ 70,20,000 + 5,700 = 70,25,700
๐ โ
Final: 702 clicks of +10,000 and 57 clicks of +100
๐ โ Question 8
How many lakhs make a billion?
๐ โ
Answer:
๐น 1 lakh = 100,000
๐น 1 billion = 1,000,000,000
๐น Number of lakhs in a billion = 1,000,000,000 รท 100,000 = 10,000
โ๏ธ Final: 10,000 lakhs
๐ โ Question 9
You are given two sets of number cards numbered from 1โ9. Place a number card in each box below to get the (a) largest possible sum
(b) smallest possible difference of the two resulting numbers.
๐ โ Answer:
๐น (a) Largest possible sum
๐ธ Make both numbers as large as possible by placing the largest digits in the highest places (each set used separately).
โ๏ธ Final: 7-digit number = 9876543, 5-digit number = 98765
๐น (b) Smallest possible difference
๐ธ To minimize the difference, make the 7-digit number as small as possible and the 5-digit number as large as possible (each from its own set).
โ๏ธ Final: 7-digit number = 1234567, 5-digit number = 98765
๐ โ Question 10
You are given some number cards; 4000, 13000, 300, 70000, 150000, 20, 5. Using the cards get as close as you can to the numbers below using any operation you want. Each card can be used only once for making a particular number.
(a) 1,10,000: Closest I could make is 4000 ร (20 + 5) + 13000
= 1,13,000
(b) 2,00,000:
(c) 5,80,000:
(d) 12,45,000:
(e) 20,90,800:
๐ โ
Answer:
๐น (b) 2,00,000
๐ธ 150000 + 70000 = 220000
๐ธ 4000 ร 5 = 20000
๐ธ 220000 โ 20000 = 200000
๐ โ
Final: 150000 + 70000 โ (4000 ร 5) = 2,00,000
๐น (c) 5,80,000
๐ธ 70000 ร 5 = 350000
๐ธ 4000 ร 20 = 80000
๐ธ 150000 + 350000 = 500000
๐ธ 500000 + 80000 = 580000
๐ โ
Final: 150000 + (70000 ร 5) + (4000 ร 20) = 5,80,000
๐น (d) 12,45,000 (closest)
๐ธ 70000 + 150000 = 220000
๐ธ 220000 + 13000 = 233000
๐ธ 233000 ร 5 = 1165000
๐ธ 4000 ร 20 = 80000
๐ธ 1165000 + 80000 = 1245000
๐ธ 1245000 + 300 = 1245300
๐ธ Difference from 12,45,000 = 1245300 โ 1245000 = 300
๐ โ
Final: 5 ร (150000 + 70000 + 13000) + (4000 ร 20) + 300 = 12,45,300 (300 more)
๐น (e) 20,90,800 (closest)
๐ธ 13000 + 150000 = 163000
๐ธ 163000 ร 5 = 815000
๐ธ 20 + 4000 = 4020
๐ธ 4020 ร 300 = 1206000
๐ธ 1206000 + 70000 = 1276000
๐ธ 815000 + 1276000 = 2091000
๐ธ Difference from 20,90,800 = 2091000 โ 2090800 = 200
๐ โ
Final: 5 ร (150000 + 13000) + (300 ร (4000 + 20)) + 70000 = 20,91,000 (200 more)
๐ โ Question 11
Find out how many coins should be stacked to match the height of the Statue of Unity. Assume each coin is 1 mm thick.
๐ โ
Answer:
๐น Height of Statue of Unity = 182 m
๐น 1 mm = 0.001 m
๐ธ Number of coins = 182 รท 0.001
๐ธ Number of coins = 182000
๐ โ
Final: 1,82,000 coins
๐ โ Question 12
Grey-headed albatrosses have a roughly 7-feet wide wingspan. They are known to migrate across several oceans. Albatrosses can cover about 900โ1000 km in a day. One of the longest single trips recorded is about 12,000 km. How many days would such a trip take to cross the Pacific Ocean approximately?
๐ โ
Answer:
๐น Fast estimate (1000 km/day):
๐ธ Days = 12000 รท 1000
๐ธ Days = 12
๐น Slow estimate (900 km/day):
๐ธ Days = 12000 รท 900
๐ธ Days = 13.33 (approx)
๐ โ Final: Approximately 12 to 14 days
๐ โ Question 13
A bar-tailed godwit holds the record for the longest recorded non-stop flight. It travelled 13,560 km from Alaska to Australia without stopping. Its journey started on 13 October 2022 and continued for about 11 days. Find out the approximate distance it covered every day. Find out the approximate distance it covered every hour.
๐ โ
Answer:
๐น Approximate distance per day
๐ธ Total distance = 13560 km
๐ธ Total time = 11 days
๐ธ Distance per day = 13560/11 km
๐ธ Distance per day = 1232.727… km
๐ โ
Final: Approximately 1233 km per day
๐น Approximate distance per hour
๐ธ Total hours in 11 days = 11 ร 24
๐ธ Total hours = 264
๐ธ Distance per hour = 13560/264 km
๐ธ Distance per hour = 51.3636… km
๐ โ
Final: Approximately 51 km per hour
๐ โ Question 14
Bald eagles are known to fly as high as 4500โ6000 m above the ground level. Mount Everest is about 8850 m high. Aeroplanes can fly as high as 10,000โ12,800 m. How many times bigger are these heights compared to Somuโs building?
๐ โ Answer:
๐น From the lesson context, Somuโs building height = 10 m.
๐น Bald eagles
๐ธ 4500 รท 10 = 450
๐ธ 6000 รท 10 = 600
๐ โ
Final: Bald eagles fly about 450โ600 times higher than Somuโs building.
๐น Mount Everest
๐ธ 8850 รท 10 = 885
๐ โ
Final: Mount Everest is about 885 times higher than Somuโs building.
๐น Aeroplanes
๐ธ 10000 รท 10 = 1000
๐ธ 12800 รท 10 = 1280
๐ โ
Final: Aeroplanes fly about 1000โ1280 times higher than Somuโs building.
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OTHER IMPORTANT QUESTIONS
( MODEL QUESTION PAPER )
ESPECIALLY MADE FROM THIS CHAPTER ONLY
๐ต Section A โ Very Short Answer (1 ร 6 = 6 marks)
๐ โ Question 1
What is the place value of 7 in the number 7,53,214?
๐ โ
Answer:
๐น The digit 7 is in the lakh place
๐น Place value of 7 = 7 ร 1,00,000
๐น Place value = 7,00,000
๐ โ Question 2
Write the smallest 6-digit number.
๐ โ
Answer:
๐น The smallest 6-digit number is 1,00,000
๐ โ Question 3
How many zeros are there in one crore?
๐ โ
Answer:
๐น One crore has 7 zeros
๐ โ Question 4
Write 3,45,00,000 in words (Indian system).
๐ โ
Answer:
๐น Three crore forty-five lakh
๐ โ Question 5
Which number is greater: 9,87,654 or 9,78,456?
๐ โ
Answer:
๐น Both numbers have 6 digits
๐น At the ten-thousands place, 8 > 7
๐น 9,87,654 is greater
๐ โ Question 6
Round 6,48,372 to the nearest thousand.
๐ โ
Answer:
๐น Hundreds digit is 3
๐น Rounded value = 6,48,000
๐ข Section B โ Short Answer I (2 ร 6 = 12 marks)
๐ โ Question 7
Write the place value of each digit in 4,62,815.
๐ โ
Answer:
๐น 4 = 4,00,000
๐น 6 = 60,000
๐น 2 = 2,000
๐น 8 = 800
๐น 1 = 10
๐น 5 = 5
๐ โ Question 8
Write in numerals: Seven crore eight lakh six thousand forty-two.
๐ โ
Answer:
๐น Seven crore = 7,00,00,000
๐น Eight lakh = 8,00,000
๐น Six thousand = 6,000
๐น Forty-two = 42
๐น Number = 7,08,06,042
๐ โ Question 9
Arrange in ascending order: 3,45,678; 3,54,768; 3,47,568.
๐ โ
Answer:
๐น Compare digit by digit from left
๐น Ascending order
๐น 3,45,678 < 3,47,568 < 3,54,768
๐ โ Question 10
Write 5,03,08,019 in words.
๐ โ
Answer:
๐น Five crore three lakh eight thousand nineteen
๐ โ Question 11
Find the difference between the Indian and International place value systems.
๐ โ
Answer:
๐น Indian system uses lakh and crore
๐น International system uses million and billion
๐ โ Question 12
Round 9,84,216 to the nearest ten thousand.
๐ โ
Answer:
๐น Thousands digit is 4
๐น Rounded value = 9,80,000
๐ก Section C โ Short Answer II (3 ร 10 = 30 marks)
๐ โ Question 13
Write the number name of 6,08,45,219.
๐ โ
Answer:
๐น Six crore eight lakh forty-five thousand two hundred nineteen
๐ โ Question 14
Compare 8,25,416 and 8,52,164 using place value.
๐ โ
Answer:
๐น Both numbers have 6 digits
๐น At the ten-thousands place, 2 < 5
๐น 8,52,164 is greater
๐ โ Question 15
Write in numerals: Ninety-two million four hundred six thousand eight.
๐ โ
Answer:
๐น Ninety-two million = 92,000,000
๐น Four hundred six thousand = 406,000
๐น Eight = 8
๐น Number = 92,406,008
๐ โ Question 16
Round 7,48,962 to the nearest lakh.
๐ โ
Answer:
๐น Ten-thousands digit is 4
๐น Rounded value = 7,00,000
๐ โ Question 17
Write any three uses of large numbers in daily life.
๐ โ
Answer:
๐น Population counting
๐น Government budgeting
๐น Distance measurement in space
๐ โ Question 18
Write the expanded form of 5,03,207.
๐ โ
Answer:
๐น 5,00,000 + 3,000 + 200 + 7
๐ โ Question 19
Write the successor of 9,99,999.
๐ โ
Answer:
๐น Successor = 10,00,000
๐ โ Question 20
Explain why estimation is useful.
๐ โ
Answer:
๐น It makes calculations easier
๐น It saves time
๐น It gives a close approximate value
๐ โ Question 21
Write the number with 6 in lakh place and 4 in hundred place.
๐ โ
Answer:
๐น One such number is 6,00,400
๐ โ Question 22
What is the face value of 8 in 8,73,945?
๐ โ
Answer:
๐น Face value of 8 is 8
๐ด Section D โ Long Answer (4 ร 8 = 32 marks)
๐ โ Question 23
Write the number 7,84,26,513 in expanded form and words.
๐ โ
Answer:
๐น Expanded form
๐ธ 7,00,00,000 + 80,00,000 + 4,00,000 + 20,000 + 6,000 + 500 + 10 + 3
๐น In words
๐ธ Seven crore eighty-four lakh twenty-six thousand five hundred thirteen
๐ โ Question 24
Arrange 6,48,921; 6,84,219; 6,49,218 in descending order.
๐ โ
Answer:
๐น Compare from leftmost digit
๐น Descending order
๐ธ 6,84,219 > 6,49,218 > 6,48,921
๐ โ Question 25
Explain the Indian place value system with an example.
๐ โ
Answer:
๐น Indian system uses ones, tens, hundreds, thousands, lakhs, crores
๐น Example: 3,45,67,218
๐ธ Three crore forty-five lakh sixty-seven thousand two hundred eighteen
๐ โ Question 26
Round 9,63,417 to the nearest ten thousand and explain the steps.
๐ โ
Answer:
๐น Ten-thousands digit is 6
๐น Thousands digit is 3
๐น Rounded value = 9,60,000
๐ โ Question 27
Write five mistakes students should avoid while dealing with large numbers.
๐ โ
Answer:
๐น Wrong comma placement
๐น Mixing number systems
๐น Missing zeros
๐น Wrong rounding
๐น Incorrect reading
๐ โ Question 28
Write the predecessor and successor of 10,00,000.
๐ โ
Answer:
๐น Predecessor = 9,99,999
๐น Successor = 10,00,001
๐ โ Question 29
Explain how large numbers help us understand real-world data.
๐ โ
Answer:
๐น Used in population data
๐น Used in science and space
๐น Used in economics and planning
๐ โ Question 30
Write 8,03,47,615 in words and international system.
๐ โ
Answer:
๐น Indian system
๐ธ Eight crore three lakh forty-seven thousand six hundred fifteen
๐น International system
๐ธ Eighty million three hundred forty-seven thousand six hundred fifteen
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