7th Maths : Term 2 Unit 1 : Number System : Exercise 1.5 : Miscellaneous Practice problems, Challenge Problems, Text Book Back Exercises Questions with Answers, Solution

**Exercise
1.5**

__Miscellaneous
practice problems__

** **

**1. Write the following decimal numbers in the place
value table.**

**(i) 247.36**

**(ii) 132.105 **

**Answer: **

** **

**2. Write each of the following as decimal number.**

i) 300 + 5 + 7/10 + 9/100 +
2/1000 = 305792

ii) 1000 + 400 + 30 + 2 +
6/10 + 7/100 = 143267

** **

**3. Which is greater?**

**(i) 0.888 (or) 0.28**

The whole number parts of the two decimal numbers are equal.

Comparing the digits of tenth place, 8 > 2

So, 0.888 > 0.28

The greater number is **0.888.**

**(ii) 23.914 (or) 23.915**

The two numbers have same digits upto hundredth place.

But the thousandth place of 5 > 4.

So, 23.915 > 23.914

The greater number is **23.915.**

** **

**4. In a 25 m
swimming competition, the time taken by 5 swimmers A, B, C, D and E are 15.7 seconds,
15.68 seconds, 15.6 seconds, 15.74 seconds and 15.67 seconds respectively. Identify
the winner.**

The time taken by 5 swimmers A, B, C, D and E are 15.7, 15.68, 15.6,
15.74, 15.67 seconds.

The whole parts of the two decimal numbers are equal.

So, Comparing the tenth place, 6 < 7

The numbers which have 6 in the tenth places are 15.68, 15.6, 15.67.

Comparing the hundred the place,

0 < 7 < 8

So, 15.6 < 15.67 < 15.68

The smaller decimal number is 15.6.

The swimmer who takes less time is the winner.

**So, the winner is C
(15.6 seconds)**

** **

**5. Convert the following decimal numbers into fractions.**

**(i) 23.4**

**23.4 **= 23 + ( 4÷2 / 10÷2 ) = 23 + 2/5

= 23 (2 / 5) = 117 / 5

** (ii) 46.301**

**46.301 **= 46 + (301 / 1000)

= 46301 / 1000

** **

**6. Express the following in kilometres using decimals.**

**(i)
256 m**

** ****(ii) 4567 m**

**i) 256 m** = 256/1000 km = 0.256 km

**ii) 4567 m** = 4567/1000 km = 4.567 km

** **

**7.
There are 26 boys and 24 girls in a class. Express the fractions of boys and girls
as decimal numbers.**

Number of boys = 26

Number of girls = 24

Total students = 50

Boys = 26×2 / 50×2 = 52 / 100 = 0.52

Girls = 24×2 / 50×2 = 48 / 100 = 0.48

** **

__Challenge
Problems__

** **

**8. Write the following amount using decimals.**

**(i) 809 rupees 99 paise**

= 809 + 99/100 = ₹809.99

** ****(ii) 147 rupees 70 paise**

= 147 + 70/100 = ₹ 147.70

** **

**9.
Express the following in metres using decimals.**

**(i)
1328 cm**

**(ii)
419 cm**

**i) 1328 cm **= 1328 / 100 m = 13.28 m

**ii) 419 cm **= 419 / 100 m = 4.19 m

** **

**10.
Express the following using decimal notation.**

**(i)
8 m 30 cm in metres**

8 m 30 cm = 8.30 m

**(ii)
24 km 200 m in kilometres**

24 km 200 m = 24.200 km

** **

**11.
Write the following fractions as decimal numbers.**

**(i) **23 / 10000 = 0.0023

**(ii) **421 / 100 = 4.21

**(iii) **37 / 10 = 3.7

** **

**12.
Convert the following decimals into fractions and reduce them to the lowest form.
**

**(i)
2.125 **

**(ii)
0.0005 **

**(i) 2.125**

= 2 + ( 125÷125 / 1000÷125 ) / 125

= 2 + 1 / 8 = 17 / 8

**ii) 0.0005**

= 5÷5 / 10000÷5

= 1 / 2000

** **

**13.
Represent the decimal numbers 0.07 and 0.7 on a number line.**

**Answer: **

The number line of 0.07 and
0.7.

** **

**14.
Write the following decimal numbers in words.**

**(i)
4.9**

**(ii)
220.0**

**(iii)
0.7**

**(iv)
86.3**

** **

**15.
Between which two whole numbers the given numbers lie? **

**(i)
0.2 **

0 and 1

**(ii)
3.4**

3 and 4

**(iii)
3.9 **

3 and 4

**(iv)
2.7**

2 and 3

**(v)
1.7 **

l and 2

**(vi)
1.3 **

1 and 2

** **

**16.
By how much is 9 /10 km less than 1 km. Express the same in decimal form. **

1 – 9/10 km

10–9 / 10 = 1/10 = 0.1 km

__ANSWERS:__

**Exercise 1.5**

1.

2. (i) 305.792 (ii)
1432.67

3. (i) 0.888 (ii)
23.915

4. C is the winner
(15.6 s)

5. (i) 117/5 (ii)
46301/1000

6. (i) 0.256* km *(ii) 4.567* km *

7. Boys = 0.52;
Girls=0.48

**Challenge problems **

8. (i) ₹809.99 (ii)
₹147.70

9. (i) 13.28* m *(ii) 4.19* m *

10.(i) 8.30* m *(ii) 24.200* km *

11. (i) 0.0023 (ii)
4.21 (iii) 3.7

12. (i) 17/8 (ii) 1/2000

13.

14. (i) four and nine
tenths (ii) Two hundred and twenty (iii)
seven tenths (iv) Eighty six and three tenths

15.(i) 0 and 1 (ii) 3
and 4 (iii) 3 and 4 (iv) 2 and 3 (v) 1
and 2 (vi) 1 and 2

16. 0.1* km*

* *

Tags : Questions with Answers, Solution | Number System | Term 2 Chapter 1 | 7th Maths , 7th Maths : Term 2 Unit 1 : Number System

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7th Maths : Term 2 Unit 1 : Number System : Exercise 1.5 | Questions with Answers, Solution | Number System | Term 2 Chapter 1 | 7th Maths

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