Question

give a rough estimate by rounding off to nearest hundred and also closer estimate by rounding off to nearest tens .
a) 439+334+4317
b)108734- 47599​

Answer 1

Answer:

439 + 334 + 4,317

 

Rounding off 439 to the nearest hundreds, we get 400

 

Rounding off 334 to the nearest hundreds, we get 300

And, rounding off 4,317 to the nearest hundreds, we get 4,300

 

Therefore, 400 + 300 + 4,300 = 5,000

 

It means that answer is equal to 5,000 when we round off different terms to the nearest hundreds.

Rounding off 439 to the nearest tens, we get 440

 

Rounding off 334 to the nearest tens, we get 330

 

And, rounding off 4,317 to the nearest tens, we get 4,320

 

Therefore, 440 + 330 + 4,320 = 5,090

 

It means that answer is equal to 5,090 when we round off different terms to the nearest tens.

 

Solution (b)

 

1,08,734 – 47,599

 

Rounding off 1,08,734 to the nearest hundreds, we get 1,08,700

 

And rounding off 47,599 to the nearest hundreds, we get 47,600

 

Therefore, 1,08,700-47,600=61,100

 

It means that answer is equal to 61,100 when we round off the terms to the nearest hundreds.

 

 

Rounding off 1,08,734 to the nearest tens, we get 1,08,730

 

 

And rounding off 47,599 to the nearest tens, we get 47,600

 

Therefore, 1,08,730-47,600=61,130

 

It means that answer is equal to 61,130 when we round off terms to the nearest tens.

 

Solution (c)

 

8,325 – 491

 

Rounding off 8,325 to the nearest hundreds, we get 8,300

 

And, rounding off 491 to the nearest hundreds, we get 500

 

Therefore, 8,300-500=7,800

 

It means that answer is equal to 7,800 when we round off terms to the nearest hundreds.

 

 

Rounding off 8,325 to the nearest tens, we get 8,330

 

 

And, rounding off 491 to the nearest tens, we get 490

 

Therefore, 8,330-490=7,840

 

It means that answer is equal to 7,840 when we round off terms to the nearest tens.

 

Solution (d)

 

4,89,348 – 48,365

 

Rounding off 4,89,348 to the nearest hundreds, we get 4,89,300

 

And, rounding off 48,365 to the nearest hundreds, we get 48,400

 

Therefore, 4,89,300-48,400=4,40,900

 

It means that answer is equal to 4,40,900 when we round off terms to the nearest hundreds.

 

 

Rounding off 4,89,348 to the nearest tens, we get 4,89,350

 

 

And, rounding off 48,365 to the nearest tens, we get 48,370

 

Therefore, 4,89,350-48,370=4,40,980

 

It means that answer is equal to 4,40,980 when we round off terms to the nearest tens.

Step-by-step explanation:

Answer 2

(a) 439 + 334 + 4317

Rounding off to nearest hundreds

439 + 334 + 4317 = 400 + 300 + 4300

= 5000

Rounding off to nearest tens

439 + 334 + 4317 = 440 + 330 + 4320

= 5090

(b) 108734 – 47599

Rounding off to nearest hundreds

108734 – 47599 = 108700 – 47600

= 61100

Rounding off to nearest tens

108734 – 47599 = 108730 – 47600

= 61130

(c) 8325 – 491

Rounding off to nearest hundreds

8325 – 491 = 8300 – 500

= 7800

Rounding off to nearest tens

8325 – 491 = 8330 – 490

= 7840

(d) 489348 – 48365

Rounding off to nearest hundreds

489348 – 48365 = 489300 – 48400

= 440900

Rounding off to nearest tens

489348 – 48365 = 489350 – 48370

= 440980

Four more examples are as follows

(i) 4853 + 662

Rounding off to nearest hundreds

4853 + 662 = 4800 + 700

= 5500

Rounding off to nearest tens

4853 + 662 = 4850 + 660

= 5510

(ii) 775 – 390

Rounding off to nearest hundreds

775 – 390 = 800 – 400

= 400

Rounding off to nearest tens

775 – 390 = 780 – 400

= 380

(iii) 6375 – 2875

Rounding off to nearest hundreds

6375 – 2875 = 6400 – 2900

= 3500

Rounding off to nearest tens

6375 – 2875 = 6380 – 2880

= 3500

(iv) 8246 – 6312

Rounding off to nearest hundreds

8246 – 6312 = 8200 – 6300

= 1900

Rounding off to nearest tens

8246 – 6312 = 8240 – 6310

= 1930