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Class 7 Maths: Large Numbers Around Us, 8 practice questions with answers

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These are 8 practice questions on Chapter 1, Large Numbers Around Us, of the new NCERT Class 7 Maths textbook, Ganita Prakash, Part 1. Each has a worked answer and the textbook page it comes from. They cover fixing misplaced commas and where the two comma styles first differ, sharing a sum in arab and lakh, rounding up and rounding down, choosing how to round a count, estimating a product, how many digits a sum has, a quick way to divide by 25, and how big a crore is. Try each one on paper before you open the answer.

These questions are our own, drafted with AI help. Every number was re-computed by a test script. Each question has its own setting, not one of the chapter's worked examples or exercises with new numbers. No practising teacher has reviewed them yet. If you find a mistake, please tell us.

What the chapter says you need

Facts from the NCERT textbook (Ganita Prakash, Grade 7, Part 1, Chapter 1, printed pages 1 to 23):

Reading and writing large numbers

Question 1. A school notice board shows the town's budget as "₹34,82,05,00", with the commas in the wrong places. (a) Put the commas in the right places in the Indian style, and say the number in crores, lakhs and thousands. (b) Up to how many digits do the Indian and American comma styles put the commas in the same places? Where do they first differ, and why?

Answer: (a) ₹3,48,20,500, which is 3 crore 48 lakh 20 thousand 500; (b) the two styles agree up to 5 digits and first differ at 6 digits. (a) Ignore the wrong commas: the digits are 34820500, which is 8 digits. In the Indian style the first comma comes after the last three digits, and then after every two digits: 3,48,20,500. So it is 3 crore 48 lakh 20 thousand 500. The notice put a comma before the last two digits, which no rule allows. (b) Both styles put the first comma after the last three digits. After that the Indian style groups by 2 and the American style groups by 3. A number with up to 5 digits has only one comma at most, so both styles write it the same way (48,205 in each). From 6 digits on, a second group is needed, and there the styles differ: 7,31,904 in the Indian style and 731,904 in the American style. (Indian and American grouping, page 8.)

Question 2. A scholarship fund holds ₹4 arab 60 crore. (a) How many crores is that? (b) It is shared equally among 2,000 students. How many lakh rupees does each student get?

Answer: (a) 460 crore; (b) 23 lakh rupees each. (a) One arab is 100 crore, so 4 arab is 400 crore, and 400 + 60 = 460 crore. (b) One crore is 100 lakh, so 460 crore is 460 × 100 = 46,000 lakh. Shared among 2,000 students, each gets 46,000 ÷ 2,000 = 23 lakh rupees, which is ₹23,00,000. (Lakh, crore and arab, page 8.)

Rounding and estimating

Question 3. A cook has 2,364 pilgrims to feed and packs food in boxes that each serve 50 people. How many boxes should she pack? Raju has ₹2,364 and each notebook costs ₹50. How many notebooks can he buy? Both start with 2,364 ÷ 50, so why are the answers different?

Answer: 48 boxes, but only 47 notebooks. 2,364 ÷ 50 = 47.28. For the pilgrims, 47 boxes serve 47 × 50 = 2,350 people and 14 pilgrims would be left hungry, so the cook must round up to 48 boxes. For the notebooks, Raju can only buy whole notebooks he can pay for in full: 47 notebooks cost ₹2,350 and a 48th would cost ₹2,400, which is more than he has, so he must round down to 47 notebooks. The division is the same, but one situation needs enough and the other needs no more than he can afford. (Rounding up and rounding down, page 10.)

Question 4. A district has 3,47,862 voters. Three reports give the count as 3,48,000, as 3,50,000 and as 3,00,000. (a) To which place has each report rounded, and how far is each from the exact number? (b) Which figure would suit a newspaper headline, and which is better for ordering voter slips? Explain.

Answer: (a) 3,48,000 is to the nearest thousand (138 more), 3,50,000 to the nearest ten thousand (2,138 more) and 3,00,000 to the nearest lakh (47,862 less); (b) 3,50,000 for a headline, 3,48,000 for the slips. (a) 3,48,000 is the multiple of 1,000 closest to 3,47,862, since 862 is more than 500; it is 3,48,000 − 3,47,862 = 138 more. 3,50,000 is the closest multiple of 10,000, since 7,862 is more than 5,000; it is 2,138 more. 3,00,000 is the closest multiple of 1,00,000, since 47,862 is less than 50,000; it is 47,862 less, a much bigger error. (b) A headline only needs to give an idea of the size, so "about 3.5 lakh voters" is enough, and it is close. The 3 lakh figure is too far off even for that. Voter slips must cover every voter, so the order should be close to the exact number and not below it: 3,48,000 is only 138 above, so every voter gets one with very few left over. (Rounding up and rounding down, page 10; the nearest thousand, ten thousand and lakh, page 11.)

Question 5. A factory packs 4,980 boxes on each working day, and it works 312 days in a year. (a) Estimate the boxes packed in the year by rounding 4,980 up to 5,000. Is the exact total more or less than your estimate, and by how much at most? (b) Without multiplying exactly, show that the total is more than 15 lakh.

Answer: (a) about 15,60,000; the exact total is less, by 6,240; (b) even 4,900 × 312 is 15,28,800. (a) 5,000 × 312 = 15,60,000. Since 4,980 was rounded up by 20, every one of the 312 days is counted 20 boxes too many, so the estimate is too big by 20 × 312 = 6,240: the exact total is 15,60,000 − 6,240 = 15,53,760. (b) 4,980 is more than 4,900, and 4,900 × 312 = 15,28,800, which is already more than 15,00,000. So the total is more than 15 lakh. (The chapter estimates sums and differences by rounding; estimating a product the same way goes a step further.) (Estimating by rounding, pages 11 and 12.)

Products and large calculations

Question 6. (a) How many digits can the sum of two 6-digit numbers have? Use the smallest and the greatest 6-digit numbers to decide. (b) Can such a sum ever have 8 digits?

Answer: (a) 6 or 7 digits; (b) no. (a) 1,00,000 is the least number with 6 digits, so the smallest sum is 1,00,000 + 1,00,000 = 2,00,000, which has 6 digits. The greatest 6-digit number is 9,99,999, so the greatest sum is 9,99,999 + 9,99,999 = 19,99,998, which has 7 digits. Every sum lies between these two, so it has 6 or 7 digits. Both happen: 1,20,000 + 3,40,000 = 4,60,000 has 6 digits, and 6,00,000 + 7,00,000 = 13,00,000 has 7. (b) No: the largest possible sum, 19,99,998, is less than 1,00,00,000, the smallest 8-digit number. (Using the smallest and greatest numbers of a given number of digits, pages 2 and 15.)

Question 7. Multiplying by 25 can be done by multiplying by 100 and dividing by 4. Turn the idea round to find a quick way to divide by 25, and use it to work out 3,700 ÷ 25 and 9,250 ÷ 25 in your head.

Answer: multiply by 4 and divide by 100: 3,700 ÷ 25 = 148 and 9,250 ÷ 25 = 370. Since 25 × 4 = 100, dividing by 25 gives the same answer as dividing by 100 and then multiplying by 4, or multiplying by 4 first and then dividing by 100. For 3,700: 3,700 × 4 = 14,800, and 14,800 ÷ 100 = 148. Check: 148 × 25 = 3,700. For 9,250: 9,250 × 4 = 37,000, and 37,000 ÷ 100 = 370. Check: 370 × 25 = 9,250. (Multiplying by 5 and by 25 through 10 and 100, pages 13 and 14.)

Question 8. A school library has 12,000 books. (a) How many libraries of that size would you need to hold 1 crore books? (b) A town has 2,50,000 people, and each owns 40 books on average. Do they own more or less than 1 crore books in all?

Answer: (a) 834 libraries; (b) exactly 1 crore. (a) One crore is 1,00,00,000. 1,00,00,000 ÷ 12,000 = 833.33, so 833 libraries are not quite enough and 834 are needed. (b) 2,50,000 × 40 = 1,00,00,000, which is exactly 1 crore books. Work it in steps: 2,50,000 × 4 = 10,00,000 (10 lakh), and 10 lakh × 10 = 100 lakh = 1 crore. Comparing a crore with a familiar thing, a whole school library, shows how big it is: more than 800 such libraries. (Lakh and crore, page 8; getting a feel for large numbers by comparing them with familiar ones, page 3.)

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Sources

All opened and read on 1 November 2026. Page numbers are the printed page numbers of the textbook; printed page = PDF page for this chapter.

The rules are from the textbook pages above. The questions, worked answers and checks are our own, and every number was re-computed by script. This guide is general information; follow your teacher and the textbook.

Practise with the worksheet: Large Numbers Around Us, Class 7 worksheet. Printable, in English, Hindi and Marathi, with an answer key.