The DAV Maths Book Class 5 Solutions and **DAV Class 5 Maths Chapter 9 Worksheet 1** Solutions of Rounding Numbers offer comprehensive answers to textbook questions.

## DAV Class 5 Maths Ch 9 Worksheet 1 Solutions

Question 1.

Round off the following numbers to the nearest ten.

(a) 31

Solution:

31 → 30

(31 is nearer to 30 than 40)

(b) 68

Solution:

68 → 70

(68 is nearer to 70 than 60)

(c) 43

Solution:

43 → 40

(43 is nearer to 40 than 50)

(d) 94

Solution:

94 → 90

(94 is nearer to 90 than 100)

(e) 199

Solution:

199 → 200

(199 is nearer to 200 than 190)

(f) 349

Solution:

349 → 350

(349 is nearer to 350 than 340)

(g) 521

Solution:

521 → 520

(521 is nearer to 520 than 530)

(h) 1,099

Solution:

1,099 → 1,100

(1,099 is nearer to 1,100 than 1090)

(i) 85

Solution:

85 → 90

(85 is halfway between 80 and 90 so we round off 85 to 90)

(j) 145

Solution:

145 → 150

(145 is halfway between 140 and 150 so we round 145 to 150)

**DAV Class 5 Maths Chapter 9 Worksheet 1 Notes**

Whole numbers:

The numbers including 0 and the natural numbers, are called whole numbers.

Example: 0, 1, 2, 3, 4,…..

- Multiples of 10 = 10, 20, 30, 40, 50,……..
- Multiples of 100 = 100, 200, 300, 400, 500,………
- Multiples of 1000 = 1000, 2000, 3000, 4000,………

In our daily lives, we come across several situations involving the use of numbers. Sometimes, we do not state the exact number as an answer, instead, we put forth a number that is the nearest multiple of 10 or 100 1000, etc. This is known as rounding the numbers.

Example.

Mamta has collected stamps. Meena asked how many stamps she collected.

Mamta said that she had collected about 600 stamps.

Meena asked, tell me the exact number.

Mamta answered 593 stamps. So, Mamta rounded off 593 to 600.

Rounding off to the nearest ten (10).

Example 1.

Raju has 53 toffees. Round off 53 to the nearest ten.

Solution:

53 lies between 50 and 60 (multiples of 10).

53 is nearer to 50 than 60.

So, we can say that Raju has about 50 toffees.

Let us round off the following numbers to the nearest ten.

- 78 → 80 (78 is nearer to 80 than 70)
- 168 → 170 (168 is nearer to 170 than 160)
- 85 → 90 (85 is halfway between 80 and 90 so we round 85 to 90)
- 1022 → 1020 (1022 is nearer to 1020 than 1030)
- If the digit in the one’s place is 0, 1, 2, 3, or 4, round off to the nearest multiple of 10 which is smaller than the number.
- If the digit in the one’s place is 5, 6, 7, 8, or 9, round off to the nearest multiple of 10, which is greater than the number.