RD Sharma Solutions Class 7 Decimals Exercise 3.2

RD Sharma Solutions Class 7 Chapter 3 Exercise 3.2

RD Sharma Class 7 Solutions Chapter 3 Ex 3.2 PDF Download

Exercise 3.2

 

Q1. Find the product:

(i) 4.74 x 10

Shifting the decimal point by one place to the right

4.74 x 10=47.4

(ii) 0.45 x 10

Shifting the decimal point by one place to the right

0.45×10=4.5

(iii) 0.0215 x 10

Shifting the decimal point by one place to the right

0.0215×10=0.215

(iv) 0.0054 x 100

Shifting the decimal point by two places to the right

0.0054×100=0.054

 

Q2. Find the product:

(i) 35.853 x 100

Shifting the decimal point by two places to the right

35.853=3585.3

(ii) 42.5 x 100

Shifting the decimal point by two places to the right

42.5×100=4250

(iii) 12.075 x 100

Shifting the decimal point by two places to the right

12.075×100=1207.5

(iv) 100 x 0.005

Shifting the decimal point by two places to the right

0.005×100=0.5

 

Q3. Find the product:

(i) 2.506 x 1000

Shifting the decimal point by three places to the right

2.506×1000=2506

(ii) 20.708 x 1000

Shifting the decimal point by three places to the right

20.708×1000=20708

(iii) 0.0529 x 1000

Shifting the decimal point by three places to the right

0.0529×1000=52.9

(iv) 1000 x 0.1

Shifting the decimal point by three places to the right

0.1×1000=100

 

Q4. Find the product:

(i) 3.4 x 17

Multiply the number without looking into the decimal points

3.4×17=578

Mark the decimal point in the product to have one place of decimal as there in the given decimal

=57.8

(ii) 0.745 x 12

Multiply the number without looking into the decimal points

745×12=8940

Mark the decimal point in the product to have three places of decimal as there in the given decimal

0.745 x 12=8.940

  

(iii) 28.73 x 47

Multiply the number without looking into the decimal points

2873×47=135031

Mark the decimal point in the product to have two places of decimal as there in the given decimal

28.73×47=1350.31

 

(iv) 0.0415 x 59

Multiply the number without looking into the decimal points

415×59=24485

Mark the decimal point in the product to have two places of decimal as there in the given decimal

0.0415×59=2.4485

 

Q5. Find:

(i) 1.07 x 0.02

Multiply the number without looking into the decimal points

107×2=214

Sum of the decimal places in the given decimals is 2+2=4

Mark the decimal point in the product to have four places of decimals

1.07×0.02=0.0214

 

(ii) 211.9 x 1.13

Multiply the number without looking into the decimal points

2119×113=239447

Sum of the decimal places in the given decimals is 1+2=3

Mark the decimal point in the product to have three places of decimals

211.9×1.13=239.447

 

(iii) 10.05 x 1.05

Multiply the number without looking into the decimal points

1005×105=105525

Sum of the decimal places in the given decimals is 2+2=4

Mark the decimal point in the product to have four places of decimals

10.05×1.05=10.5525

 

(iv) 13.01 x 5.01

Multiply the number without looking into the decimal points

1301×501=651801

Sum of the decimal places in the given decimals is 2+2=4

Mark the decimal point in the product to have four places of decimals

13.01×5.01=65.1801

 

Q6. Find the area of a rectangle whose length is 5.5 m and breadth is 3.4 m.

We have

Length of rectangle=5.5m

Breadth of rectangle=3.4m

Area of rectangle=length X Breadth

= 5.5 x 3.4

=18.7\(m^{2}\)

 

Q7. If the cost of a book is Rs 25.75, find the cost of 24 such books.

Cost of one book=Rs.25.75

Therefore cost of 24 books=25.75x 24

=Rs.618.00

 

Q8. A car covers a distance of 14.75 km in one litre of petrol. How much distance will it cover in 15.5 litres of petrol?

We have,

Distance covered in one litre of petrol=14.75km

Distance covered in 15.5 litres of petrol=14.75 x 15.5

=228.625km

 

Q9. One kg of rice costs Rs 42.65. What will be the cost of 18.25 kg of rice?

Cost of one kg rice= 42.65

Cost of 18.25kg= 42.65 x 18.25

=Rs.778.3625

 

Q10. One metre of cloth costs Rs 152.50. What is the cost of 10.75 metres of cloth?

We have,

One metre of cloth cost= Rs.152.50

Cost of 10.75 metres=10.75 x 152.50

=Rs.1639.375