6th Maths Term 1 Unit 1 Exercise 1.4 Solutions | Estimation and Rounding Off

Exercise 1.4: Questions with Answers & Solution

Chapter: 6th Maths : Term 1 Unit 1 : Numbers

1. Fill in the blanks.

(i) The nearest 100 of 843 is ___________.
Answer: 800
(ii) The nearest 1000 of 756 is ___________.
Answer: 1000
(iii) The nearest 10000 of 85654 is ___________.
Answer: 90000

2. Say True or False.

(i) 8567 is rounded off as 8600 to the nearest 10.
Answer: False
(ii) 139 is rounded off as 100 to the nearest 100.
Answer: True
(iii) 1,70,51,972 is rounded off as 1,70,00,000 to the nearest lakh.
Answer: False

3. Round off the following to the given nearest place.

(i) 4,065; hundred
Solution: 4,065; hundred
Compare tenth place 6 > 5; Add ‘1’ to hundredth place and make tenth and oneth place as zero.
4,065; hundred = \( 6 > 5 \)
= 4100
(ii) 44,555; thousand
Solution: 44,555 = \( 5 = 5 \)
→ 45,000
(iii) 86,943; ten thousand
Solution: 86,943 = \( 6 > 5 \)
→ 90,000
(iv) 50,81,739; lakh
Solution: 50,81,739 = \( 8 > 5 \)
→ 51,00,000
(v) 33,75,98,482; ten crore
Solution: 33,75,98,482 = \( 3 < 5 \)
→ 30,00,00,000

4. Estimate the sum

Estimate the sum of 157826 and 32469 rounded off to the nearest ten thousand.

Solution:

Sum of 157826 and 32469

Actual:

1,57,826 + 32,469 ---------- 1,90,295 ----------

157826 + 32469 = 1,90,295

Estimated sum = 1,60,000
nearest ten thousand = 30,000

1,60,000 + 30,000 ---------- 1,90,000 ----------

Hence Estimated sum of 157826 and 32469 = 1,90,000

5. Estimate by rounding off each number to the nearest hundred.

(i) 8074 + 4178
Solution: Estimate:
nearest hundred = 8100 + 4200
= 12,300
Hence estimated of 8074 + 4178 = 12,300
(ii) 1768977 + 130589
Solution: Estimate:
nearest hundred = 1768977 + 130589
= 1899600
Hence estimated of 1768977 + 130589 = 1899600

6. Word Problem

The population of a city was 43,43,645 in the year 2001 and 46,81,087 in the year 2011. Estimate the increase in population by rounding off to the nearest thousand.

Solution:

Population of city in 2001 = 43,43,645
in 2011 = 46,81,087

Estimate increase in population nearest to thousand is

Population in 2011 = 46,81,000 Population in 2001 = 43,44,000 ---------- 3,37,000 ----------

Increase in population between 2011 to 2001 is 3,37,000

Objective Type Questions

7. The number which on rounding off to the nearest thousand gives 11000 is

  • (a) 10345
  • (b) 10855
  • (c) 11799
  • (d) 10056
Answer: (b) 10855

8. The estimation to the nearest hundred of 76812 is

  • (a) 77000
  • (b) 76000
  • (c) 76800
  • (d) 76900
Answer: (c) 76800

9. The number 9785764 is rounded off to the nearest lakh as

  • (a) 9800000
  • (b) 9786000
  • (c) 9795600
  • (d) 9795000
Answer: (a) 9800000

10. The estimated difference of 167826 and 2765 rounded off to the nearest thousand is

  • (a) 180000
  • (b) 165000
  • (c) 140000
  • (d) 155000
Answer: (b) 165000

Answer Key Recap: Exercise 1.4

  • 1) (i) 800 (ii) 1000 (iii) 90,000
  • 2) (i) False (ii) True (iii) False
  • 3) (i) 4100 (ii) 45,000 (iii) 90,000 (iv) 51,00,000 (v) 30,00,00,000
  • 4) 1,90,000
  • 5) (i) 12,300 (ii) 18,99,600
  • 6) 3,37,000
  • 7) (b) 10855
  • 8) (c) 76800
  • 9) (a) 9800000
  • 10) (b) 165000