CBSE Class 7 Mathematics Large Numbers Around Us Practice Paper Assignment Set 02 with Answers

Practice Paper 02 for CBSE Class 7 Maths Ganita Prakash Chapter 1 Large Numbers Around Us carries 40 marks and 20 questions across Sections A to E, each solved step by step below. This paper focuses on calculations with large numbers: multiplying and subtracting lakhs and crores, divisibility by 9 and digit sums, the greatest and smallest numbers of a given number of digits, rounding to the nearest lakh, ten lakh and crore, number names in both systems, and case studies on device sales, a census bar graph and per-person spending.

Section A: Multiple Choice Questions (1 Mark Each)

Section B: Short Answer Questions (2 Marks Each)

Question 11. Write the number name of 760840120 in both Indian and International number systems.
Answer:
Indian commas: 76,08,40,120 (76 crore | 08 lakh | 40 thousand | 120).
Indian system: Seventy-six crore eight lakh forty thousand one hundred twenty.
International commas: 760,840,120 (760 million | 840 thousand | 120).
International system: Seven hundred sixty million eight hundred forty thousand one hundred twenty.
In simple words: Place the commas for each system first, then read the groups with their names.

Teacher's Note:
1. The lakh period here is 08, so we say "eight lakh".
2. The ones period 120 is read as "one hundred twenty" in both systems.

Question 12. A publishing company printed 15,64,000 textbooks in a year. Estimate the number of books printed to the nearest lakh and ten lakh.
Answer:
Nearest lakh: 15,64,000 lies between 15,00,000 and 16,00,000; the ten thousands digit is 6 (5 or more), so it rounds up to 16,00,000.
Nearest ten lakh: 15,64,000 lies between 10,00,000 and 20,00,000; the lakh digit is 5 (5 or more), so it rounds up to 20,00,000.
In simple words: About 16 lakh books to the nearest lakh, and about 20 lakh to the nearest ten lakh.

Teacher's Note:
1. Look at the digit just to the right of the place you are rounding to.
2. Rounding to a bigger place gives a rougher estimate.

Question 13. A mobile application has 3,24,85,263 active users. Round this number off to the nearest crore and also nearest ten lakh.
Answer:
Nearest crore: the ten lakh digit is 2 (less than 5), so round down to 3,00,00,000 (3 crore).
Nearest ten lakh: the lakh digit is 4 (less than 5), so round down to 3,20,00,000 (3 crore 20 lakh).
In simple words: 3 crore 24 lakh is closer to 3 crore, and closer to 3 crore 20 lakh than to 3 crore 30 lakh.

Teacher's Note:
1. Places in 3,24,85,263 from the left: crore 3, ten lakh 2, lakh 4.
2. Rounding down keeps the rounding digit and turns everything after it into zeros.

Question 14. Find the difference between the greatest 8-digit number and smallest 7-digit number.
Answer:
Greatest 8-digit number = 9,99,99,999.
Smallest 7-digit number = 10,00,000.
Difference = 9,99,99,999 − 10,00,000 = 9,89,99,999.
In simple words: Write the two numbers and subtract.

Teacher's Note:
1. The greatest 8-digit number has eight 9s; the smallest 7-digit number is 1 followed by six 0s.
2. Check: 9,89,99,999 + 10,00,000 = 9,99,99,999.

Section C: Short Answer Questions (3 Marks Each)

Question 15. Ramesh counted the population of five villages:
1st: 25,640
2nd: 98,453
3rd: 76,231
4th: 1,23,679
5th: 89,420
(a) Find the total population.
(b) Round off the total to nearest lakh.
Answer:
(a) Add in steps: 25,640 + 98,453 = 1,24,093.
1,24,093 + 76,231 = 2,00,324.
2,00,324 + 1,23,679 = 3,24,003.
3,24,003 + 89,420 = 4,13,423.
(b) 4,13,423: the ten thousands digit is 1 (less than 5), so it rounds down to 4,00,000 (4 lakh).
In simple words: Add the five populations to get 4,13,423, which is about 4 lakh.

Teacher's Note:
1. Adding two numbers at a time reduces mistakes.
2. Quick check by estimating: 26 + 98 + 76 + 124 + 89 thousand ≈ 413 thousand.

Question 16. A company had a turnover of ₹4,68,75,999 in 2021 and ₹5,84,23,071 in 2022.
(a) Find the increase in turnover.
(b) Write the increase in International number system.
(c) Estimate the total turnover in both years.
Answer:
(a) Increase = ₹5,84,23,071 − ₹4,68,75,999 = ₹1,15,47,072.
(b) In International commas: ₹11,547,072, read as Eleven million five hundred forty-seven thousand seventy-two rupees.
(c) Round each to the nearest crore: ₹4,68,75,999 ≈ ₹5 crore and ₹5,84,23,071 ≈ ₹6 crore, so the total is about ₹11 crore.
A closer estimate: exact total = ₹10,52,99,070 ≈ ₹10.5 crore.
In simple words: Subtract to find the increase, rewrite it with 3-digit groups, and add the two years roughly.

Teacher's Note:
1. The nearest-crore estimate (₹11 crore) is rough; rounding to the nearest ten lakh (4.7 + 5.8 = 10.5 crore) is closer.
2. Check (a): 4,68,75,999 + 1,15,47,072 = 5,84,23,071.

Question 17. A stadium has 89 rows of chairs. Each row contains 725 chairs.
(a) How many chairs are there in total?
(b) If each ticket costs ₹150, what is the total ticket revenue for full occupancy?
(c) If only 80 rows are fully filled, what is the revenue then?
Answer:
(a) Total chairs = 89 × 725 = 90 × 725 − 725 = 65,250 − 725 = 64,525 chairs.
(b) Revenue = 64,525 × ₹150 = ₹96,78,750.
(c) Chairs in 80 rows = 80 × 725 = 58,000.
Revenue = 58,000 × ₹150 = ₹87,00,000.
In simple words: Multiply rows by chairs per row, then multiply the chairs by the ticket price.

Teacher's Note:
1. Breaking 89 into 90 − 1 makes the multiplication easy.
2. Revenue for 80 rows is less by 9 rows × 725 × ₹150 = ₹9,78,750.

Section D: Long Answer Question (5 Marks)

Question 18. A metro city consumes 34,27,896 units of water in summer, 28,46,721 in winter, and 25,74,986 in monsoon. Students analyzed this seasonal data to understand resource usage patterns and presented it using a bar graph for better interpretation.
(a) Find the total annual consumption.
(b) Round the total to the nearest lakh and ten lakh.
(c) Write the total in both Indian and International number systems.
(d) Estimate the average monthly consumption.
Answer:
(a) Total = 34,27,896 + 28,46,721 + 25,74,986.
34,27,896 + 28,46,721 = 62,74,617, and 62,74,617 + 25,74,986 = 88,49,603 units.
(b) Nearest lakh: the ten thousands digit is 4 (less than 5), so 88,00,000.
Nearest ten lakh: the lakh digit is 8 (5 or more), so 90,00,000.
(c) Indian system: 88,49,603 = Eighty-eight lakh forty-nine thousand six hundred three.
International system: 8,849,603 = Eight million eight hundred forty-nine thousand six hundred three.
(d) A year has 12 months. Using the rounded total, 88,00,000 ÷ 12 ≈ 7,33,333, so the average is about 7.3 lakh units per month.
(Exactly: 88,49,603 ÷ 12 ≈ 7,37,467 units per month.)
In simple words: Add the three seasons, round the total, write its number names, and share it over 12 months.

Teacher's Note:
1. The three seasons together make up one year, so their sum is the annual consumption.
2. For an estimate, divide a rounded total; the exact value 7,37,467 is close.
3. Both Indian and International names describe the same 7-digit number.

Section E: Case Study Based Questions (4 Marks Each)

Question 19. Case Study – Tech Startup
Ritika, a Class VII student, conducted a survey on tech startups for her Mathematics project. She studied a startup that sold a record number of digital devices over two consecutive years. In 2021, it sold 1,24,79,283 units, and in 2022, the figure rose to 1,43,60,018 units. Each device was priced at ₹23,999. Her analysis helped her understand the impact of large numbers in real-world financial data.
Answer the following:
(a) What was the total number of units sold?
(b) Estimate total income earned (round price to ₹24,000).
(c) Express 2022 sales in International system.
(d) Find the difference in sales between the two years.
Answer:
(a) Total units = 1,24,79,283 + 1,43,60,018 = 2,68,39,301 units.
(b) Estimated income = 2,68,39,301 × ₹24,000 = ₹6,44,14,32,24,000.
That is about ₹64,414 crore (2.68 crore × 24,000 ≈ 64,400 crore).
(c) 1,43,60,018 = 14,360,018, read as Fourteen million three hundred sixty thousand eighteen.
(d) Difference = 1,43,60,018 − 1,24,79,283 = 18,80,735 units.
In simple words: Add the two years, multiply by ₹24,000 for the income, regroup the digits in threes, and subtract for the difference.

Teacher's Note:
1. The answer key in the source gave ₹64,41,43,22,400 (about ₹6441 crore) for (b); the correct product is ₹6,44,14,32,24,000, about ₹64,414 crore.
2. Multiplying by 24,000 = multiplying by 24 and then by 1000.

Question 20. Case Study – Census Project
During the National Census Project, Anika and her classmates were assigned to study the population growth and budget allocation of a local district. They found that in 2011, the population was 28,64,374, which increased to 36,75,928 by the year 2021. That same year, the district received a government budget of ₹2,78,64,000 for development works and public welfare. Using this data, the students analyzed the population growth, numerical representations, estimations, and per capita spending for a better understanding of data interpretation in real-life applications.
Answer the following:
(a) What was the population increase in 10 years?
(b) Write the budget in both number systems.
(c) Round off the 2021 population to nearest lakh.
(d) Approximate how much was spent per person.
Answer:
(a) Increase = 36,75,928 − 28,64,374 = 8,11,554.
(b) Indian system: ₹2,78,64,000 = Two crore seventy-eight lakh sixty-four thousand rupees.
International system: ₹27,864,000 = Twenty-seven million eight hundred sixty-four thousand rupees.
(c) 36,75,928: the ten thousands digit is 7 (5 or more), so it rounds up to 37,00,000.
(d) Spending per person = budget ÷ population ≈ ₹2,78,64,000 ÷ 37,00,000.
In lakhs: 278.64 lakh ÷ 37 lakh = 278.64 ÷ 37 ≈ 7.5 (since 37 × 7.5 = 277.5).
Using the exact population, ₹2,78,64,000 ÷ 36,75,928 ≈ ₹7.58.
So about ₹7.6 (roughly ₹8) per person.
In simple words: Subtract for the increase, write the budget both ways, round the population, and divide the budget by the population.

Teacher's Note:
1. The source answer key gave ₹75.82 per person for (d); that is 10 times too big, since 37 lakh × ₹76 would be about ₹28 crore, not ₹2.8 crore.
2. Check a per-person answer by multiplying back: 37,00,000 × 7.5 ≈ 2,77,50,000.
3. The bar graph shows the same two populations in millions: 2.86 million and 3.68 million.