- Books Name
- CBSE Class 6 Mathematics Book

- Publication
- Param Publication

- Course
- CBSE Class 6

- Subject
- Mathmatics

**Large Numbers in Practice**

we have learnt that we use centimetre (cm) as a unit of length. For measuring the length of a pencil, the width of a book or notebooks etc., we use centimetres. Our ruler has marks on each centimetre. For measuring the thickness of a pencil, however, we find centimetre too big. We use millimetre (mm) to show the thickness of a pencil.

(a) 10 millimetres = 1 centimetre

To measure the length of the classroom or the school building, we shall find centimetre too small. We use metre for the purpose.

(b) 1 metre = 100 centimetres = 1000 millimetres

Even metre is too small, when we have to state distances between cities, say, Delhi and Mumbai, or Chennai and Kolkata. For this we need kilometres (km).

We have done a lot of problems that have addition, subtraction, multiplication and division.

We will try solving some more here.

**Ex :** Population of Sundarnagar was 2,35,471 in the year 1991. In the year 2001 it was found to be increased by 72,958. What was the population of the city in 2001?

**Sol.** Population of the city in 2001 = Population of the city in 1991 + Increase in population

= 2,35,471 + 72,958

Now, 235471

__+ 72958__

308429

Salma added them by writing 235471 as 200000 + 35000 + 471 and 72958 as 72000 + 958.

She got the addition as 200000 + 107000 + 1429 = 308429.

Mary added it as 200000 + 35000 + 400 + 71 + 72000 + 900 + 58 = 308429

Answer : Population of the city in 2001 was 3,08,429.

All three methods are correct.

**Ex:** In one state, the number of bicycles sold in the year 2002-2003 was 7,43,000. In the year 2003-2004, the number of bicycles sold was 8,00,100. In which year were more bicycles sold? and how many more?

**Sol.** Clearly, 8,00,100 is more than 7,43,000. So, in that state, more bicycles were sold in the year 2003-2004 than in 2002-2003.

Now, 800100

__– 743000__

057100

Check the answer by adding

743000

__+ 57100__

800100 (the answer is right).

Answer : 57,100 more bicycles were sold in the year 2003-2004.