NCERT Solution class 7 Mathematics EXERCISE- 2.5

NCERT Solution class 7 Mathematics EXERCISE- 2.5

 

                     CHAPTER – 2

                    EXERCISE – 2.5

Q1. Which is greater?

(i) 0.5 or 0.05

SOLUTION:-

= 0.5 > 0.05

(ii) 0.7 or 0.5

SOLUTION:-

= 0.7 > 0.5

(iii) 7 or 0.7

SOLUTION:-

= 7 > 0.7

(iv) 1.37 or 1.49

SOLUTION:-

= 1.37<1.49

(v) 2.03 or 2.30

SOLUTION:-

= 2.03< 2.30

(vi) 0.8 or 0.88

SOLUTION:-

= 0.8 < 0.88

Q2.Express as rupees using decimals:

(i) 7 paise

SOLUTION:-

= 0.07

(ii) 7 rupees7 paise

SOLUTION:-

= 7.07

(iii) 77 rupees 77 paise

SOLUTION:-

= 77.77

(iv) 50 paise

SOLUTION:-

= 0.50

(v) 235 paise

SOLUTION:-

= 2.35

Q3. (i) Express 5cm in meter and kilometer

SOLUTION:-

WE KONOW,

= 1 meter = 100cm

Then,

= 1 cm = (1/100) m

= 5 cm =

(5/100)

= 0.05 m

Now,

= 1 km = 1000m

Then,

= 1m = (1/1000) km

= 0.05 m = (0.05/1000)

= 0.00005 km

(ii) Express 35 mm in cm , m and km

SOLUTION:-

We know that,

= 1cm = 10mm

Then,

= 1 mm = (1/10) cm

= 35mm= (35/10) cm

= 3.5 cm

And,

= 1 meter = 100 cm

Then,

= 1 cm = (1/100) m

= 3.5 cm = (3.5 /100) m

= ( 35/1000) m

= 0.035 m

Now,

= 1 km = 1000 m

Then,

= 1m = (1/1000) km

= 0.035 m = (0.035 /1000)

= 0.000035 km

Q4. Express in kg:

(i) 200g

SOLUTION:-

We know that ,

= 1 kg = 1000g

Then,

= 1g = (1/1000) kg

= 200g = (200/1000) kg

= (2/10)

= 0.2 kg

(ii) 3470 g

SOLUTION:-

We know that,

= 1 kg = 1000g

Then,

=1 g = (1/1000) kg

= 3470 g = (3470/1000)kg

= (3470/100)

= 3.470 kg

(iii) 4 kg 8 g

SOLUTION:-

We know that ,

= 1 kg = 1000g

Then,

= 1g = (1/1000) kg

= 4 kg 8 g = 4 kg + (8/1000) kg

= 4kg + 0.008

= 4.008 kg

Q5. Write the following decimal numbers in the expanded form :

(i) 20.03

SOLUTION:-

We have,

20.03 = ( 2 x 10) + ( 0 x 1) + (0  x (1/10))  + ( 3 x (1/100))

(ii) 2.03

SOLUTION:-

We have,

2.03 = ( 2 x 1) + ( 0 x ( 1/10)) + (3 x (1/100))

(iii) 200.03

SOLUTION:-

We have,

200.03 = ( 2 x 100) + ( 0 x 10) + ( 0x1) +  ( 0 x (1/10)) + ( 3 x (1/100))

(iv) 2.034

SOLUTION:-

We have,

2.034 = (2 x1) + ( 0 x (1/10)) + ( 3 x (1/100)) + ( 4 x (1/1000))

Q6. Write the place value of 2 in the  following decimal numbers :

(i) 2.56

SOLUTION:-

From the question, we observe that ,

The place value of 2 in 2.56 in ones

(ii) 21.37

SOLUTION:-

From the question , we observe that

The places value of 2 in 21.37 is tens

(iii) 10.25

SOLUTION:-

From the question, we obseve that ,

The place value of 2 in 10.25 is tenths.

(iv) 9.42

SOLUTION:-

From the observes that ,

The place value of 2 in 9.42 is hundredth

(v) 63.352

SOLUTION:-

From the question , we observe that,

The places value of 2 in 63.352  is thousandth.

Q7. Dinesh went from place A to place B and from there to place C.  A is 7.5 km from B and B is 12.7 km from C . Ayub went place A to place D and from there to place C. D is 9.3 km from A and C is 11.8 km from D. Who travelled more and by how much?

SOLUTION:-

 

From the question, it is given that ,

Distance travelled by dinesh = AB + BC

= 7.5 + 12.7

= 20.2 KM

Dinesh travelled 20.2 km

Distance travelled by ayub = AD + DC

= 9.3 + 11.8

= 21.1 KM

Ayub travelled 21.1 km

Clearly ayub travelled more distance by = ( 21.1 + 20.2)

= 0.9 km

Ayub travelled 0.9 km more than Dinesh .

Q8. Shyama bought 5 kg 300 g apples and 3 kg 250 g mangoes. SARALA bought 4 kg 800 g oranges and 4 kg 150 g bananas Who bought more fruits ?

SOLUTION:-

From the question , It is given that ,

Fruits bought by shyama = 5 kg 300 g

= 5 kg + ( 300/1000) kg

= 5 kg + 0.3 kg

= 5.3 kg

Fruits bought by sarala = 4 kg 800 g + 4 kg 150 g

= (4 + (800/1000) + (4 + (150/1000))

= ( 4+ 0.8) kg +(4 + 150) kg

= 4.8 kg + 4.150 kg

= 8.950 kg

So , sarala bought more fruits.

Q9. How much less is 28 km than 42.6 km?

SOLUTION:-

Now, we have to find the difference of 42.6 km and 28  km

= 42.6 – 28.0

= 14.6

14.6 km less is 28 km than 42.6 km.

 

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