Gujarat Board GSEB Textbook Solutions Class 6 Maths Chapter 1 Knowing Our Numbers Ex 1.3 Textbook Questions and Answers.

## Gujarat Board Textbook Solutions Class 6 Maths Chapter 1 Knowing Our Numbers Ex 1.3

Question 1.

Estinwie 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 and subtraction, and estimate their outcome.

Solution:

(a) 730 + 998

730 → 700 [Rounded off to hundreds]

998 → 1000 [Rounded off to hundreds]

Estimated sum = 700 + 1000 = 1700

(b) 796 – 314

796 → 800 [Rounded off to hundreds]

314 → 300 [Rounded off to hundreds]

Estimated difference 800 – 300 = 500

(c) 12,904 + 2888

12,904 → 13,000 [Rounded off to hundreds]

2,888 → 3,000 [Rounded off to hundreds]

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

(d) 28,292 – 21,496

28,292 → 28,000 [Rounded off to hundreds]

21,496 → 21,000 [Rounded off to hundreds]

Estimated difference = 28000 – 21000 = 7000

Note: Make ten more such examples and do yourself.

Question 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) 8,325 – 491

(d) 4,89,348 – 48,365

Solution:

(a) 439 + 334 + 4,317

Rough estimate 400 + 300 + 4300 = 5,000 Again,

Closer estimate = 440 + 330 + 4,320 = 5,090

(b) 1,08,734 – 47,599

Since

Rough estimate = 1,08,700 – 47,600 = 61,100 Again,

Closer estimate = 1,08,730 – 47,600 = 61,130

(c) 8,325 – 491

Since,

Rough estimate 8,300 – 500 = 7,800 Again.

Closer estimate = 8,330 – 490 = 7,840

(d) 4,89,348 – 48,365

Since,

Rough estimate = 4,89,300 – 48,400 = 4,40,900 Again,

Closer estimate = 4,89,350 – 48,370 = 4,40,980

Note: Make four more such examples and do yourself.

Question 3.

Estimate the following products using general rule:

(a) 578 x 161

(b) 5,281 x 3,491

(c) 1,291 x 592

(d) 9,250 x 29

Make four more such examples and do yourself.

Note: Round the numbers up or down before the calculation.

Solution:

(a) 578 x 161

578 → 600 [Rounding off to hundreds]

161 → 200 [Rounding off to hundreds]

∴Estimated product 600 x 200 = 1,20,000

(b) 5,281 x 3,491

5,281 → 5,000 [Rounding off to thousands]

3,491 → 3,500 [Rounding off to hundreds]

∴Estimated product = 5,000 x 3,500 = 1,75,00,000

(c) 1,291 x 592

1,291 → 4 1,300 [Rounding off to hundreds]

592 → 600 [Rounding off to hundreds]

∴Estimated product = 1,300 x 600 = 7,80,000

(d) 9250 x 29

9,250 → 9,300 [Rounding off to hundreds]

29 → 30 [Rounding off to tens]

∴Estimated product = 9300 x 30 = 279000

Note: Make four more such examples and do yourself.