# NCERT Solution Class 6 Maths Chapter – 1 Knowing Our Numbers

**Exercise 1.1 **

**Question 1: Answer the following questions**

**a) How many ten thousand make up 1 lakh?**

** Answer:** Ten

**b) How many hundred thousand make up one million?**

**Answer:** Ten

**c) How many ten lakh make up one crore?**

**Answer:** Ten

**d) One crore is equivalent to how many millions?**

**Answer:** Ten

**Question 2: With proper use of periods, express the following in numeric format.**

**a) Seventy two lakh fifty six thousand four hundred six**

**b) Eight crore six lakh fifty one**

**c) Six crore sixty two lakh thirty one thousand two hundred three.**

**d) Seventy six million five hundred ninety thousand four hundred and three**

**e) Twenty two lakh forty thousand nine**

**Answer:**

a) 72, 56, 406

b) 80, 06, 00,051

c) 6, 62, 31, 203

d) 76, 590, 403

e) 22, 40, 009

**Question 3: With proper use of period, give the names as per Indian numerical system for below numbers.**

**a) 98606873 **

**b) 9657394**

**c) 99900046**

**d) 98543812**

**Answer:**

a) 9, 86, 06, 873

Nine crore eighty six lakh six thousand eight hundred seventy three

b) 96, 57,394

Nine six lakh fifty seven thousand three hundred ninety four

c) 9, 99, 00, 046

Nine crore ninety nine lakh forty six

d) 9, 85, 43, 812

Nine crore eighty-five lakh forty three thousand eight hundred twelve.

**Exercise – 1.2**

**Question 1: A dress exhibition was held for 4 days in a mall. The number of shopkeeper sold dress at the counter on the 1st , 2nd , 3rd and final day was 1094, 1812, 2050 and 2051. Find the total number shopkeepers sold dress on all the four days.**

**Answer:**

Number of dress sold on 1st day= 1,094

Number of dress sold by shopkeepers on 2nd day= 1,812

Number of dress sold by shopkeepers on 3rd day= 2,050

Number of dress sold by shopkeepers on 4th day = + 2,751

Total dress sold by shopkeepers 1,094+1,812+2,050+ 2,751 = 7,707

Therefore, shopkeepers sold 7,707 dress on all the 4 days.

**Question 2: Vivek Dhankrish is a famous baseball player. He scored so far 6980 runs in league matches. He wants to complete 10,000 runs. How many runs should he take to reach 10,000?**

**Answer:**

Runs to take = 10,000

Runs to be scored = –6,980

Runs required = 3,020

Therefore, he needs 3,020 more runs.

**Question 3: In an college election, the successful student registered 5,77,500 votes and his rival student got 3,48,700 votes. Give the margin of the successful student win the election.**

**Answer:**

Number of votes secured by successful student= 5,77,500

votes secured by his opponent student =–3,48,700

Margin between them = 2,28,800

Therefore, the successful candidate won by of 2,28,800 votes.

**Question 4: Dress store sold dress worth Rs.2,85,891 in the first week of June and dress worth Rs.4,00,768 in the 2nd week of the month. How much was the sale for the two weeks together? In which week was the sale greater and by how much?**

**Answer:**

Dress sold in 1st week = 2,85,891

Dress sold in 2nd week = + 4,00,768

Total dress sold= 6,86,659

Since, 4,00,768,> 2,85,891

Therefore sale of 2nd week is greater than that of 1st week.

Dress sold in 2nd week =4,00,768

Dress sold in first week= – 2,85,891

More dress sold in second week= 1,14,877

Therefore, 1,14,877 more dress were sold in 2nd week.

**Question 5: Find the difference between the largest and the smallest number that can be written using the digits 6, 2, 7, 4, 3 each only once.**

**Answer:** Largest five digit number using digits 6,2,7,4,3 = 76432

Smallest five-digit number using digits 6,2,7,4,3

= –23467

Difference= 52965

Therefore, the difference is 52965.

**Question 6: A factory machine, on an average, manufactures 2,825 bolts a day. How many bolts did it produce in the month of March 2006?**

**Answer:** Number of bolts manufactured in one day

= 2,825

Number of days in the month of march(31 days)

= 2,825 x 31 = 87,575

Therefore the factory machine produced 87,575 bolts in the month of march 2006.

**Question 7: A shopkeeper had Rs.78,592 with her. He placed an order for purchasing 40 TV sets at Rs. 1,200 each. How much money will he have after the product is purchased? Answer:** The cost of one TV= Rs. 200

Total cost of 40 TVs = 1200 x 40=Rs. 48,000

Now,

Total money with shopkeeper =Rs.78,592

The sum of Money spent by him= –Rs. 48,000

Money left remaining with him= Rs. 30,592

Therefore, Rs.30,592 will remain with him after the product is been purchased.

**Question 8: A boy multiplied 7236 by 65 instead by multiplying it with 56. By how much was his answer larger than the exact answer?**

**Answer:** Wrongly multiplied answer = 7236 x 65 = 470340

Exact answer = 7236 x 56 = 405216

**Question 9: To knit a pant 2 m 15 cm cotton cloth is needed. Out of 40 m cotton cloth, how many pants can be knitted?**

**Answer:** Cotton Cloth required to knit one pant = 2 m 15 cm

= 2 x 100 cm + 15 cm

= 215 cm

Length of cotton cloth = 40 m = 40 x 100 cm = 4000 cm

Number of pants can be Knitted = 4000 ¸215= 18

Therefore, 18 shirts can be knitted.

**Question 10: Dresses is packed in cardboards, each weighing 4 kg 500 g. How many such cardboards can be loaded in a van, which is not able to carry beyond 800 kg?**

**Answer:** The weight of one box = 4 kg 500 g = 4 x 1000 g + 500 g = 4500 g

Maximum load can be loaded in van = 800 kg = 800 x 1000 g = 800000 g

Number of boxes = 800000¸4500 =177

Therefore, 177 boxes can be loaded.

**Question 11: The distance between the office and the house of an employee’s house is 1 km 875 m. Every day he walks two ways. Find the total distance by him in 6 days.**

**Answer:**

Distance between Office and home = 1.875 km

Distance between home and office = + 1.875 km

Total distance covered in 1 day = 3.750 km

Distance covered in 6 days

= 3.750 x 6 = 22.500 km

Therefore, 22 km 500 m distance covered in six days.

**Question 12: A bottle has four liters and 500 ml of buttermilk. In how many bottles each of 25 ml capacity, can it be filled?**

**Answer:** Capacity of buttermilk in a vessel = 4litres

500 ml =4 x 1000 ml + 500 ml = 4500 ml

Capacity of one glass = 25 ml

Number of glasses can be filled = 4500¸25=180

Therefore, 180 bottles can be filled by buttermilk.

**Exercise – 1.3**

**QUESTIONS 1: Determine the following by using general rule:**

**(i) 768 + 830**

**(ii) 596 – 340**

**(iii) 5432 + 3129**

**(iv) 24850 – 22720**

**Answer:**

(i) 768 rounding off to 800

830 rounding off to 800

Estimated sum = 1600

(ii) 596 rounding off to 600

340 rounding off to 300

Estimated difference = 300

(iii) 5432 rounding off to 5000

3129 rounding off to 3000

Estimated sum = 8000

(iv) 24850 rounding off to 25000

22720 rounding off to 23000

Estimated difference= 2000

**Question 2: Estimate the following (by rounding off the values to nearest hundreds) and a closer estimate (by rounding off to nearest tens):**

**(i) 440 + 324 + 4650**

**(ii) 1,08,747 – 47,593**

**(iii) 8235 – 392**

**(iv) 4,89,338 – 48,375**

**Answer:**

**(i)** 440 rounding off to 400

324 rounding off to 300

4650 rounding off to 4700

Estimated sum = 5400

**(ii)** 108747 rounding off to 108700

47593 rounding off to 47600

Estimated difference = 61100

**(iii)** 8235 rounding off to 8200

392 rounding off to 400

Estimated difference = 7800

**(iv)** 489338 rounding off to 489300

48375 rounding off to 48400

Estimated difference = 440900

**Question 3: Determine the following by using general rule:**

**(i) 568 x 180**

**(ii) 4280 x 2490**

**(iii) 1190 x 589**

**(iv) 5270 x 29**

**Answer:**

**(i)** 568 x 180

568 rounding off to 600

180 rounding off to 200

The estimated product = 600 x 200 = 1,20,000

**(ii)** 4280 x 2490

4280 rounding off to 4300

2490 rounding off to 2500

The estimated product = 4300 x 2500 = 1,07,50,000

**(iii)** 1190 x 589

1190 rounding off to 1200

589 rounding off to 600

The estimated product = 1200 x 600 = 7,20,000

**(iv)** 5270 x 29

5270 rounding off to 5500

29 rounding off to 30

The estimated product = 5500 x 30 = 1,65,000