6 th maths ex 1.4

KALAIMAGAL ACADEMY

6th Standard Samacheer Kalvi Maths

Chapter 1: Numbers — Exercise 1.4 Solutions

EXERCISE 1.4

1. Fill in the blanks.

1. The nearest 100 of 843 is 800.
   Explanation: The tens digit is 4 (< 5), so we round down.
2. The nearest 1000 of 756 is 1000.
   Explanation: The hundreds digit is 7 (≥ 5), so we round up.
3. The nearest 10000 of 85654 is 90000.
   Explanation: The thousands digit is 5 (≥ 5), so we round up.

2. Say True or False.

1. 8567 is rounded off as 8600 to the nearest 10.
   Answer: False
   Reason: To the nearest 10, the ones digit is 7, so it rounds up to 8570, not 8600.
2. 139 is rounded off as 100 to the nearest 100.
   Answer: True
   Reason: The tens digit is 3 (< 5), so we round down to 100.
3. 1,70,51,972 is rounded off as 1,70,00,000 to the nearest lakh.
   Answer: False
   Reason: The ten-thousands digit is 5, so it rounds up to the nearest lakh, which is 1,71,00,000.

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

1. 4,065; hundred → 4,100
   (Tens digit is 6 ≥ 5, round up)
2. 44,555; thousand → 45,000
   (Hundreds digit is 5 ≥ 5, round up)
3. 86,943; ten thousand → 90,000
   (Thousands digit is 6 ≥ 5, round up)
4. 50,81,739; lakh → 51,00,000
   (Ten-thousands digit is 8 ≥ 5, round up)
5. 33,75,98,482; ten crore → 30,00,000,000 (30 crore)
   (Crores digit is 3 < 5, round down)

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

Solution:
Rounding 1,57,826 to the nearest ten thousand → 1,60,000
Rounding 32,469 to the nearest ten thousand → 30,000
Estimated Sum = 1,60,000 + 30,000 = 1,90,000

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

1. 8074 + 4178
   8074 rounded to nearest 100 → 8100
   4178 rounded to nearest 100 → 4200
   Estimated Sum = 8100 + 4200 = 12,300
2. 1768977 + 130589
   17,68,977 rounded to nearest 100 → 17,69,000
   1,30,589 rounded to nearest 100 → 1,30,600
   Estimated Sum = 17,69,000 + 1,30,600 = 18,99,600

6. 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 in 2011 = 46,81,087 → Rounded to nearest 1000 = 46,81,000
Population in 2001 = 43,43,645 → Rounded to nearest 1000 = 43,44,000
Estimated Increase = 46,81,000 − 43,44,000 = 3,37,000