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ToggleNCERT Solution For Class 6, Maths, Chapter 1, Knowing Our Numbers, Exercise 1.3 given below.

## NCERT Solution For Class 6, Maths, Chapter 1, Knowing Our Numbers, Exercise 1.3

**Q.1. Estimate each of the following using general rule:**

**(a) 730 + 998 (b) 796 – 314 (c) 12,904 +2,888 (d) 28,292 – 21,496**

**Make ten more such examples of addition, subtraction and estimation of their outcome.**

**Ans: ****(a) 730 + 998**

730 rounds off to 700

998 rounds off to 1000

Hence, Estimated sum = 700 + 1,000 = 1,700

**(b) 796 – 314**

796 rounds off to 800

314 rounds off to 300

Hence, Estimated difference = 800 – 300 = 500

**(c) 12,904 + 2,888**

12904 rounds off to 13000

2888 rounds off to 3000

Hence, Estimated sum = 13,000 + 3,000 = 16,000

**(d) 28292 – 21496**

28292 round off to 28000

21496 round off to 21000

Hence, Estimated difference = 28,000 – 21,000 = 7,000

** ****Ten more such examples:**

(i) 530 + 480 = 500 + 500 = 1000

(ii) 4937 + 6990 = 5000 + 7000 = 12000

(iii) 5392 – 3770 = 5000 – 4000 = 1000

(iv) 6440 – 3972 = 6000 – 4000 = 2000

(v) 3175 + 1204 = 3000 + 1000 = 4000

(vi) 7112 – 5292 = 7000 – 5000 = 2000

(vii) 910 + 575 = 900 + 600 = 1500

(viii) 6200 – 4800 = 6000 – 5000 = 1000

(ix) 6731 + 1800 = 7000 + 2000 = 9000

(x) 6485 – 3319 = 6000 – 3000 = 3000

**Q.2. Give a rough estimate (by rounding off to nearest hundreds) and also a closer estimate (by rounding off to nearest tens) :**

**(a) 439 + 334 + 4,317 **

**(b) 1,08,734 – 47,599 **

**(c) 8325 – 491**

**(d) 4,89,348 – 48,365**

**Make four more such examples.**

**Ans: ****(a) ****439 + 334 + 4,317**

Round off to nearest hundreds

439 + 334 + 4,317 = 400 + 300 + 4,300 = 5000

Rounding off to nearest tens

439 + 334 + 4,317 = 440 + 330 + 4,320 = 5,090

**(b) 1,08,734 – 47,599**

Rounding off to nearest hundreds

1,08,734 – 47,599 = 1,08,700 – 47,600 = 61,100

Rounding off to nearest tens

1,08,734 – 47,599 = 1,08,730 – 47,600 = 61,130

**(c) 8,325 – 491**

Rounding off to nearest hundreds

8,325 – 491 = 8,300 – 500 = 7,800

Rounding off to nearest tens

8,325 – 491 = 8,330 – 490 = 7,840

**(d) 4,89,348 – 48,365**

Rounding off to nearest hundreds

4,89,348 – 48,365 = 4,89,300 – 48,400 = 4,40,900

Rounding off to nearest tens

4,89,348 – 48,365 = 4,89,350 – 48,370 = 440980

**Q.3. Estimate the following products using general rule: ****(a) 578 × 161 (b) 5281 × 3491 (c) 1291 × 592 (d) 9250 × 29**

**Make four more such examples.**

**Ans: ****(a) ****578 × 161**

578 rounded off to 600

161 rounded off to 200

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

**(b) 5,281 × 3,491**

5281 rounded off to 5,000

3491 rounded off to 3,500

The estimated product = 5,000 × 3,500 = 1,75,00,000

**(c) 1,291 × 592**

1291 rounded off to 1,300

592 rounded off to 600

The estimated product = 1,300 × 600 = 7,80,000

**(d) 9,250 × 29**

9250 rounded off to 9000

29 rounded off to 30

The estimated product = 9,000 × 30 = 2,70,000