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EXERCISE 2(A) 
Question 1. 
Round off each of the following to the nearest ten: 
(i) 62 
(ii) 265 
(iii) 543 
(iv) 8261 
(v) 6294 
(vi) 3008 
(vii) 72326 
Solution: 
If the digit at ones place is less than 5, replace ones digit by 0, and keep the other digit 
as they are : 
And if the digit at ones place is 5 or more than 5, increase tens digit by 1, and replace 
ones digit by 0. 
(i) 62 – 60 
(ii) 265 – 270 
(iii) 543 – 540 
(iv) 8261 – 8260 
(v) 6294 – 6290 
(vi) 3008-3010 
Question 2. 
Round off each of the following to the nearest hundred : 
(i) 748 
(ii) 784 
(iii) 2667 
(iv) 5432 
(v) 6388 
(vi) 59237 
Solution: 
If the tens digit is less than 5, replace each one of tens and once digits by 0 and keep 
the other digits as they are : 
(i) 748 – 700 
(ii) 784 – 800 
(iii) 2667 – 2700 
(iv) 5432 – 5400 
(v) 6388 – 6400 
(vi) 59237 – 59200 
Question 3. 
Round off each of the following to the nearest thousand: 
(i) 6475 
(ii) 6732 
Page 2


EXERCISE 2(A) 
Question 1. 
Round off each of the following to the nearest ten: 
(i) 62 
(ii) 265 
(iii) 543 
(iv) 8261 
(v) 6294 
(vi) 3008 
(vii) 72326 
Solution: 
If the digit at ones place is less than 5, replace ones digit by 0, and keep the other digit 
as they are : 
And if the digit at ones place is 5 or more than 5, increase tens digit by 1, and replace 
ones digit by 0. 
(i) 62 – 60 
(ii) 265 – 270 
(iii) 543 – 540 
(iv) 8261 – 8260 
(v) 6294 – 6290 
(vi) 3008-3010 
Question 2. 
Round off each of the following to the nearest hundred : 
(i) 748 
(ii) 784 
(iii) 2667 
(iv) 5432 
(v) 6388 
(vi) 59237 
Solution: 
If the tens digit is less than 5, replace each one of tens and once digits by 0 and keep 
the other digits as they are : 
(i) 748 – 700 
(ii) 784 – 800 
(iii) 2667 – 2700 
(iv) 5432 – 5400 
(v) 6388 – 6400 
(vi) 59237 – 59200 
Question 3. 
Round off each of the following to the nearest thousand: 
(i) 6475 
(ii) 6732 
(iii) 5352 
(iv) 32568 
(v) 9248 
(vi) 83294 
Solution: 
If the tens digit is 5 or more than 5, increase the hundreds digit by 1 and replace each of 
tens digit and ones digit by 0. 
(i) 6475 – 6000 
(ii) 6732 – 7000 
(iii) 25352 – 25000 
(iv) 32568 – 33000 
(v) 9248 – 9000 
(vi) 83294 – 83000 
Question 4. 
Round off 
(i) 578 to the nearest ten. 
(ii) 578 to the nearest hundred. 
(iii) 4327 to the nearest thousand. 
(iv) 32974 to the nearest ten-thousand. 
(v) 27487 to the nearest ten-thousand. 
Solution: 
(i) 578 – 580 
(ii) 578 – 600 
(iii) 4327 – 4000 
(iv) 32974 – 30000 
(v) 27487 – 30000 
Question 5. 
Round off each of the following to the nearest tens, hundreds and thousands. 
(i) 864 
(ii) 1249 
(iii) 54, 547 
(iv) 68, 076 
(v) 56, 293 
(vi) 7, 293 
(vii) 89, 24, 379  
Solution: 
(i) 864 – 860 
864 – 900 
864 – 1000 
(ii) 1249 – 1250 
1249 – 1200 
1249 – 1000 
(iii) 54, 547 – 54550 
54, 547 – 54500 
Page 3


EXERCISE 2(A) 
Question 1. 
Round off each of the following to the nearest ten: 
(i) 62 
(ii) 265 
(iii) 543 
(iv) 8261 
(v) 6294 
(vi) 3008 
(vii) 72326 
Solution: 
If the digit at ones place is less than 5, replace ones digit by 0, and keep the other digit 
as they are : 
And if the digit at ones place is 5 or more than 5, increase tens digit by 1, and replace 
ones digit by 0. 
(i) 62 – 60 
(ii) 265 – 270 
(iii) 543 – 540 
(iv) 8261 – 8260 
(v) 6294 – 6290 
(vi) 3008-3010 
Question 2. 
Round off each of the following to the nearest hundred : 
(i) 748 
(ii) 784 
(iii) 2667 
(iv) 5432 
(v) 6388 
(vi) 59237 
Solution: 
If the tens digit is less than 5, replace each one of tens and once digits by 0 and keep 
the other digits as they are : 
(i) 748 – 700 
(ii) 784 – 800 
(iii) 2667 – 2700 
(iv) 5432 – 5400 
(v) 6388 – 6400 
(vi) 59237 – 59200 
Question 3. 
Round off each of the following to the nearest thousand: 
(i) 6475 
(ii) 6732 
(iii) 5352 
(iv) 32568 
(v) 9248 
(vi) 83294 
Solution: 
If the tens digit is 5 or more than 5, increase the hundreds digit by 1 and replace each of 
tens digit and ones digit by 0. 
(i) 6475 – 6000 
(ii) 6732 – 7000 
(iii) 25352 – 25000 
(iv) 32568 – 33000 
(v) 9248 – 9000 
(vi) 83294 – 83000 
Question 4. 
Round off 
(i) 578 to the nearest ten. 
(ii) 578 to the nearest hundred. 
(iii) 4327 to the nearest thousand. 
(iv) 32974 to the nearest ten-thousand. 
(v) 27487 to the nearest ten-thousand. 
Solution: 
(i) 578 – 580 
(ii) 578 – 600 
(iii) 4327 – 4000 
(iv) 32974 – 30000 
(v) 27487 – 30000 
Question 5. 
Round off each of the following to the nearest tens, hundreds and thousands. 
(i) 864 
(ii) 1249 
(iii) 54, 547 
(iv) 68, 076 
(v) 56, 293 
(vi) 7, 293 
(vii) 89, 24, 379  
Solution: 
(i) 864 – 860 
864 – 900 
864 – 1000 
(ii) 1249 – 1250 
1249 – 1200 
1249 – 1000 
(iii) 54, 547 – 54550 
54, 547 – 54500 
54, 547 – 55000 
(iv) 68, 076 – 68, 080 
68, 076 – 68, 100 
68, 076 – 68, 000 
(v) 56, 293 – 56, 290 
56, 293 – 56, 300 
56, 293 – 56, 000 
(vi) 7, 293 – 7290 
7, 293 – 7, 300 
7, 293 – 7000 
(vii) 89, 24, 379 – 89, 24, 380 
89, 24, 379 – 89, 24, 400 
89, 24, 379 – 89, 24, 000 
Question 6. 
Round off the following to the nearest tens ; 
(i) ? 562 
(ii) 837 m 
(iii) 545 cm 
(iv) ? 27 
Solution: 
(i) ? 562 
? 562 – ? 560 
(ii) 837 m 
837 – 840 m 
(iii) 545 cm 
545 – 550 
(iv) ? 21 
? 27 – ? 30 
Question 7. 
List all the numbers which can be round off to 30. 
Solution: 
The numbers that can be rounded off to 30 are: 
26, 27, 28, 29, 31, 32, 33, 34 
Question 8. 
List all the numbers which can be rounded off to 50. 
Solution: 
The numbers that can be rounded off to 50 are: 
46, 47, 48, 49, 51, 52, 53, 54 
Question 9. 
Write the smallest and the largest numbers which are rounded off to 80. 
Solution: 
Page 4


EXERCISE 2(A) 
Question 1. 
Round off each of the following to the nearest ten: 
(i) 62 
(ii) 265 
(iii) 543 
(iv) 8261 
(v) 6294 
(vi) 3008 
(vii) 72326 
Solution: 
If the digit at ones place is less than 5, replace ones digit by 0, and keep the other digit 
as they are : 
And if the digit at ones place is 5 or more than 5, increase tens digit by 1, and replace 
ones digit by 0. 
(i) 62 – 60 
(ii) 265 – 270 
(iii) 543 – 540 
(iv) 8261 – 8260 
(v) 6294 – 6290 
(vi) 3008-3010 
Question 2. 
Round off each of the following to the nearest hundred : 
(i) 748 
(ii) 784 
(iii) 2667 
(iv) 5432 
(v) 6388 
(vi) 59237 
Solution: 
If the tens digit is less than 5, replace each one of tens and once digits by 0 and keep 
the other digits as they are : 
(i) 748 – 700 
(ii) 784 – 800 
(iii) 2667 – 2700 
(iv) 5432 – 5400 
(v) 6388 – 6400 
(vi) 59237 – 59200 
Question 3. 
Round off each of the following to the nearest thousand: 
(i) 6475 
(ii) 6732 
(iii) 5352 
(iv) 32568 
(v) 9248 
(vi) 83294 
Solution: 
If the tens digit is 5 or more than 5, increase the hundreds digit by 1 and replace each of 
tens digit and ones digit by 0. 
(i) 6475 – 6000 
(ii) 6732 – 7000 
(iii) 25352 – 25000 
(iv) 32568 – 33000 
(v) 9248 – 9000 
(vi) 83294 – 83000 
Question 4. 
Round off 
(i) 578 to the nearest ten. 
(ii) 578 to the nearest hundred. 
(iii) 4327 to the nearest thousand. 
(iv) 32974 to the nearest ten-thousand. 
(v) 27487 to the nearest ten-thousand. 
Solution: 
(i) 578 – 580 
(ii) 578 – 600 
(iii) 4327 – 4000 
(iv) 32974 – 30000 
(v) 27487 – 30000 
Question 5. 
Round off each of the following to the nearest tens, hundreds and thousands. 
(i) 864 
(ii) 1249 
(iii) 54, 547 
(iv) 68, 076 
(v) 56, 293 
(vi) 7, 293 
(vii) 89, 24, 379  
Solution: 
(i) 864 – 860 
864 – 900 
864 – 1000 
(ii) 1249 – 1250 
1249 – 1200 
1249 – 1000 
(iii) 54, 547 – 54550 
54, 547 – 54500 
54, 547 – 55000 
(iv) 68, 076 – 68, 080 
68, 076 – 68, 100 
68, 076 – 68, 000 
(v) 56, 293 – 56, 290 
56, 293 – 56, 300 
56, 293 – 56, 000 
(vi) 7, 293 – 7290 
7, 293 – 7, 300 
7, 293 – 7000 
(vii) 89, 24, 379 – 89, 24, 380 
89, 24, 379 – 89, 24, 400 
89, 24, 379 – 89, 24, 000 
Question 6. 
Round off the following to the nearest tens ; 
(i) ? 562 
(ii) 837 m 
(iii) 545 cm 
(iv) ? 27 
Solution: 
(i) ? 562 
? 562 – ? 560 
(ii) 837 m 
837 – 840 m 
(iii) 545 cm 
545 – 550 
(iv) ? 21 
? 27 – ? 30 
Question 7. 
List all the numbers which can be round off to 30. 
Solution: 
The numbers that can be rounded off to 30 are: 
26, 27, 28, 29, 31, 32, 33, 34 
Question 8. 
List all the numbers which can be rounded off to 50. 
Solution: 
The numbers that can be rounded off to 50 are: 
46, 47, 48, 49, 51, 52, 53, 54 
Question 9. 
Write the smallest and the largest numbers which are rounded off to 80. 
Solution: 
The smallest number which is rounded off to 80 is 75 
and the largest number which is rounded off to 80 is 84. 
Question 10. 
Write the smallest and the largest numbers which are rounded off to 130. 
Solution: 
The smallest number which is rounded off to 130 is 125 
and The largest number which is rounded off to 130 is 134. 
EXERCISE 2(B) 
Question 1. 
Estimate the sum of each pair of numbers to the nearest ten : 
(i) 67 and 44 
(ii) 34 and 87 
(iii) 23 and 66 
(iv) 78 and 18 
(v) 96 and 55 
(vi) 76 and 62 
(vii) 457 and 175 
(viii) 474 and 173 
(ix) 527 and 267 
Solution: 
(i) 67 and 44 
67 to the nearest ten 70 and, 44 to the nearest ten = 40 
? Required sum (70 + 40) = 110 
(ii) 34 and 87 
34 to the nearest ten = 30 and, 87 to the nearest ten = 90 
? Required sum = (30 + 90) = 120 
(iii) 23 and 66 
23 to the nearest ten = 20 and, 66 to the nearest ten = 70 
? Required sum = (20 + 70) = 90 
(iv) 78 and 18 
78 to the nearest ten = 80 and, 18 to the nearest ten = 20 
? Required sum = (80 + 20) = 100 
(v) 96 and 55 
96 to the nearest ten = 100 and, 55 to the nearest ten = 60 
? Required sum = (100 + 60) = 160 
(vi) 76 and 62 
76 to the nearest ten = 80 and, 62 to the nearest ten = 60 
? Required sum = (80 + 60) = 140 
(vii) 457 and 175 
457 to the nearest ten = 460 and, 175 to the nearest ten = 180 
? Required sum = (460 + 180) = 640 
(viii) 474 and 173 
Page 5


EXERCISE 2(A) 
Question 1. 
Round off each of the following to the nearest ten: 
(i) 62 
(ii) 265 
(iii) 543 
(iv) 8261 
(v) 6294 
(vi) 3008 
(vii) 72326 
Solution: 
If the digit at ones place is less than 5, replace ones digit by 0, and keep the other digit 
as they are : 
And if the digit at ones place is 5 or more than 5, increase tens digit by 1, and replace 
ones digit by 0. 
(i) 62 – 60 
(ii) 265 – 270 
(iii) 543 – 540 
(iv) 8261 – 8260 
(v) 6294 – 6290 
(vi) 3008-3010 
Question 2. 
Round off each of the following to the nearest hundred : 
(i) 748 
(ii) 784 
(iii) 2667 
(iv) 5432 
(v) 6388 
(vi) 59237 
Solution: 
If the tens digit is less than 5, replace each one of tens and once digits by 0 and keep 
the other digits as they are : 
(i) 748 – 700 
(ii) 784 – 800 
(iii) 2667 – 2700 
(iv) 5432 – 5400 
(v) 6388 – 6400 
(vi) 59237 – 59200 
Question 3. 
Round off each of the following to the nearest thousand: 
(i) 6475 
(ii) 6732 
(iii) 5352 
(iv) 32568 
(v) 9248 
(vi) 83294 
Solution: 
If the tens digit is 5 or more than 5, increase the hundreds digit by 1 and replace each of 
tens digit and ones digit by 0. 
(i) 6475 – 6000 
(ii) 6732 – 7000 
(iii) 25352 – 25000 
(iv) 32568 – 33000 
(v) 9248 – 9000 
(vi) 83294 – 83000 
Question 4. 
Round off 
(i) 578 to the nearest ten. 
(ii) 578 to the nearest hundred. 
(iii) 4327 to the nearest thousand. 
(iv) 32974 to the nearest ten-thousand. 
(v) 27487 to the nearest ten-thousand. 
Solution: 
(i) 578 – 580 
(ii) 578 – 600 
(iii) 4327 – 4000 
(iv) 32974 – 30000 
(v) 27487 – 30000 
Question 5. 
Round off each of the following to the nearest tens, hundreds and thousands. 
(i) 864 
(ii) 1249 
(iii) 54, 547 
(iv) 68, 076 
(v) 56, 293 
(vi) 7, 293 
(vii) 89, 24, 379  
Solution: 
(i) 864 – 860 
864 – 900 
864 – 1000 
(ii) 1249 – 1250 
1249 – 1200 
1249 – 1000 
(iii) 54, 547 – 54550 
54, 547 – 54500 
54, 547 – 55000 
(iv) 68, 076 – 68, 080 
68, 076 – 68, 100 
68, 076 – 68, 000 
(v) 56, 293 – 56, 290 
56, 293 – 56, 300 
56, 293 – 56, 000 
(vi) 7, 293 – 7290 
7, 293 – 7, 300 
7, 293 – 7000 
(vii) 89, 24, 379 – 89, 24, 380 
89, 24, 379 – 89, 24, 400 
89, 24, 379 – 89, 24, 000 
Question 6. 
Round off the following to the nearest tens ; 
(i) ? 562 
(ii) 837 m 
(iii) 545 cm 
(iv) ? 27 
Solution: 
(i) ? 562 
? 562 – ? 560 
(ii) 837 m 
837 – 840 m 
(iii) 545 cm 
545 – 550 
(iv) ? 21 
? 27 – ? 30 
Question 7. 
List all the numbers which can be round off to 30. 
Solution: 
The numbers that can be rounded off to 30 are: 
26, 27, 28, 29, 31, 32, 33, 34 
Question 8. 
List all the numbers which can be rounded off to 50. 
Solution: 
The numbers that can be rounded off to 50 are: 
46, 47, 48, 49, 51, 52, 53, 54 
Question 9. 
Write the smallest and the largest numbers which are rounded off to 80. 
Solution: 
The smallest number which is rounded off to 80 is 75 
and the largest number which is rounded off to 80 is 84. 
Question 10. 
Write the smallest and the largest numbers which are rounded off to 130. 
Solution: 
The smallest number which is rounded off to 130 is 125 
and The largest number which is rounded off to 130 is 134. 
EXERCISE 2(B) 
Question 1. 
Estimate the sum of each pair of numbers to the nearest ten : 
(i) 67 and 44 
(ii) 34 and 87 
(iii) 23 and 66 
(iv) 78 and 18 
(v) 96 and 55 
(vi) 76 and 62 
(vii) 457 and 175 
(viii) 474 and 173 
(ix) 527 and 267 
Solution: 
(i) 67 and 44 
67 to the nearest ten 70 and, 44 to the nearest ten = 40 
? Required sum (70 + 40) = 110 
(ii) 34 and 87 
34 to the nearest ten = 30 and, 87 to the nearest ten = 90 
? Required sum = (30 + 90) = 120 
(iii) 23 and 66 
23 to the nearest ten = 20 and, 66 to the nearest ten = 70 
? Required sum = (20 + 70) = 90 
(iv) 78 and 18 
78 to the nearest ten = 80 and, 18 to the nearest ten = 20 
? Required sum = (80 + 20) = 100 
(v) 96 and 55 
96 to the nearest ten = 100 and, 55 to the nearest ten = 60 
? Required sum = (100 + 60) = 160 
(vi) 76 and 62 
76 to the nearest ten = 80 and, 62 to the nearest ten = 60 
? Required sum = (80 + 60) = 140 
(vii) 457 and 175 
457 to the nearest ten = 460 and, 175 to the nearest ten = 180 
? Required sum = (460 + 180) = 640 
(viii) 474 and 173 
474 to the nearest ten = 470 and, 173 to the nearest ten = 170 
? Required sum = (470 + 170) = 640 
(ix) 527 and 267 
527 to the nearest ten = 530 and, 267 to the nearest ten = 270 
? Required sum = (530 + 270) = 800 
Question 2. 
Estimate the sum of each pair of numbers to the nearest hundred : 
(i) 336 and 782 
(ii) 546 and 342 
(iii) 270 and 495 
(iv) 4280 and 5295 
(v) 4230 and 2410 
(vi) 30047 and 39287 
Solution: 
(i) 336 and 782 
336 to the nearest hundred = 300 and, 782 to the nearest hundred = 800 
? Required sum = (300 + 800) = 1100 
(ii) 546 and 342 and, 342 to the nearest hundred = 300 
? Required sum = (500 + 300) = 800 
(iii) 270 and 495 
270 to the nearest hundred = 300 and, 495 to the nearest hundred = 500 
? Required sum = (300 + 500) = 800 
(iv) 4280 and 5295 
4280 to the nearest hundred = 4300 and, 5295 to the nearest hundred = 5300 
? Required sum = (4300 + 5300) = 9600 
(v) 4230 and 2410 
4230 to the nearest hundred = 4200 and, 2410 to the nearest hundred = 2400 
? Required number = (4200 + 2400) = 6600 
(vi) 30047 and 39287 
30047 to the nearest hundred = 30000 and, 39287 to the nearest hundred = 39300 
? Required sum = (30000 + 39300) = 69, 300 
Question 3. 
Estimate the sum of the following pair of numbers to the nearest thousand: 
(i) 53826 and 36455 
(ii) 56802 and 22475 
Solution: 
(i) 53826 and 36455 
53826 to the nearest hundred = 54000 and, 36455 to the nearest hundred = 36000 
? Required sum = (54000 + 36000) = 90000 
(ii) 56802 and 22475 
56802 to the nearest thousand = 57000 and, 22475 to the nearest thousand = 22000 
? Required sum = (57000 + 22000) = 79000 
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