NCERT Exercise 2.5 Solution-2

NCERT Exercise 2.5 Solution-2

Question (4) Express in kg (i) 200 g

Solution :

Given, 200 g

Thus, value in kg using decimal = ?

We know that, 1000 g = 1 kg

Thus, 1 g `=1/1000` kg

Thus, 200 g `=1/1000xx200` kg

`=2/10` kg

= 0.2 kg Answer

(ii) 3470 g

Solution :

Given, 3470 g

Thus, value in kg using decimal = ?

We know that, 1000 g = 1 kg

Thus, 1 g `=1/1000` kg

Thus, 3470 g `=1/1000xx3470` kg

= 3.470 kg Answer

(iii) 4 kg 8 gm

Solution :

Given, 4 kg 8 gm

Thus, value in kg using decimal = ?

We know that, 1000 g = 1 kg

Thus, 1 g `=1/1000` kg

Thus, 8 g `=1/1000xx8` kg

= 0.008 kg

Thus, 4 kg 8 g = 4 kg + 0.008 kg

= 4.008 kg Answer

(iv) 2598 mg

Solution :

Given, 2598 mg

Thus, value in kg using decimal = ?

We know that, 1000 mg = 1 gm

And 1000 g = 1 kg

Thus, 1 mg = 1/1000 g

And, 1 g = 1/1000 kg

Thus, 1 mg = 1/1000000 kg

Thus, 2598 mg `=1/1000000xx2598` kg

= 0.002598 kg

Thus, 2598 mg = 0.002598 kg Answer

Question (5) Write the following decimal numbers in the expanded form:

(i) 20.03

Solution

Given, 20.03

Answer

(ii) 2.03

Solution

Given, 2.03

Thus, expanded form of given number

Answer

(iii) 200.03

Solution

Given, 200.03

Thus, expanded form of given number

Answer

(iv) 2.034

Solution

Given, 2.034

Thus, expanded form of given number

Answer

Question (6) Write the place value of 2 in the following decimal numbers:

(i) 2.56

Solution :

Given, 2.56

Thus, place value of 2 = ?

Here, since 2 is at the ones place

Thus, place value of 2 = ones Answer

(ii) 21.37

Solution :

Given, 21.37

Thus, place value of 2 = ?

Here, since 2 is at the tens place

Thus, place value of 2 = tens Answer

(iii) 10.25

Solution :

Given, 10.25

Thus, place value of 2 = ?

Here, since 2 is at the `1/10` place, that means at tenths place

Thus, place value of 2 = tenths Answer

(iv) 9.42

Solution :

Given, 9.42

Thus, place value of 2 = ?

Here, since 2 is at the `1/100` place, that means at hundredths place

Thus, place value of 2 = hundredths Answer

(iv) 63.352

Solution :

Given, 9.42

Thus, place value of 2 = ?

Here, since 2 is at the `1/100` place, that means at hundredths place

Thus, place value of 2 = hundredths Answer

(v) 63.352

Solution :

Given, 63.352

Thus, place value of 2 = ?

Here, since 2 is at the `1/1000` place, that means at thousandths place

Thus, place value of 2 = thoudandths Answer

Question (7) 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 from 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 :

Given, Distance between A to B = 7.5 km

Distance between B to C = 12.7 km

Distance between A and D = 9.3 km

And, distance between C and D = 11.8 km

Dinesh went from A to B and from there to place C.

And Ayub went from A to D and from there to C.

Thus, who travelled more and by how much?

Distance covered by Dinesh

Since, Dinesh went from A to B and from there to place C.

Thus total distance covered by Dinesh = AB + BC

= 7.5 km + 12.7 km

= 20.2 km

Distance covered by Ayub

Since, Ayub went from A to D and from there to C

Thus total distance covered by Ayub = AD + DC

= 9.3 km + 11.8 km

= 21.1 km

Since, 21.1 km > 20.2 km

Thus, Ayub travelled more.

Difference in distance covered by Ayub and Dinesh

= Distance travelled by Ayub – Distance travelled by Dinesh

= 21.1 km – 20.2 km

= 0.9 km

Thus, Ayub travelled 0.9 km more than Dinesh Answer

Question (8) 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 fruit?

Solution :

Given, fruits bought by Shyama = 5 kg 300 g apples and 3 kg 250 g mangoes

Fruits bought by Sarala 4 kg 800 g oranges and 4 kg 150 g bananas

Thus, who bought more fruits?

Now, total fruits bought by Shyama

= 5 kg 300 g + 3 kg 250 g

= 5 kg + `300/1000` kg + 3 kg + `250/1000` kg

= 5 kg + 0.3 kg + 3 kg + 0.25 kg

= 5.03 kg + 3.25 kg

Thus, fruits bought by Shyama = 8.28 kg

Now, fruits bought by Sarala = 4 kg 800 g oranges and 4 kg 150 g bananas

= 4 kg + `800/1000` kg + 4 kg + `150/1000` kg

= 4 kg + 0.8 kg + 4 kg + 0.15 kg

= 4.8 kg + 4.15 kg

Thus fruits bought by Sarala = 8.95 kg

Now, we know that, to find greater among decimal numbers, if there is same number before decimal, then numbers given after the decimal are compared.

Here, In between 8.28 kg and 8.95 kg

The, numbers before decimal, i.e. 8 is same.

And, in between numbers are decimal, i.e. between 28 and 95

28 < 95

Thus, 8.28 < 8.95

This means 8.95 is greater.

Thus, Sarala bought more fruits. Answer

Question (9) How much less is 28 km than 42.6 km

Solution :

Given, 28 km and 42.6 km

Thus, difference between given numbers = ?

Since, 28 is less than 42

Thus, 28 < 42.6

Now,

The difference between given numbers = 42.6 km – 28.0 km

= 42.6 km – 28.0 km

= 14.6 km

Thus, 14.6 km Answer

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