- Books Name
- CBSE Class 6 Mathematics Book

- Publication
- Param Publication

- Course
- CBSE Class 6

- Subject
- Mathmatics

Publisher Update Release -> 23/8/2021 4:45 PM

**Introduction**

We use numbers and know many things about them. Numbers help us count concrete objects. They help us to say which collection of objects is bigger and arrange them in order e.g., first, second, etc. Numbers are used in many different contexts and in many ways. Think about various situations where we use numbers. List five distinct situations in which numbers are used.

We have added, subtracted, multiplied and divided them. In this chapter, we shall move forward on such interesting things with a bit of review and revision as well.

**USE OF COMMAS**

You must have noticed that in writing large numbers in the sections above, we have often used commas. Commas help us in reading and writing large numbers. In our Indian System of Numeration we use ones, tens, hundreds, thousands and then lakhs and crores. Commas are used to mark thousands, lakhs and crores. The first comma comes after hundreds place (three digits from the right) and marks thousands. The second comma comes two digits later (five digits from the right). It comes after ten thousands place and marks lakh. The third comma comes after another two digits (seven digits from the right). It comes after ten lakh place and marks crore.

**Ex:** 5, 08, 01, 592

3, 32, 40, 781

7, 27, 05, 062

Suppose a newspaper report states that Rs.2500 crore has been allotted by the government for National Highway construction. The same amount of Rs.2500 crore is sometimes expressed as Rs. 25 billion. In the Indian system, we express it as Rs. 2500 crore and in the International system, the same number is expressed as 25 billion. Hence we need to understand both the systems and their relationship.

**Ascending order **

Ascending order means arrangement from the smallest to the greatest.

**Descending order **

Descending order means arrangement from the greatest to the smallest.

Ex: Arrange the following numbers in ascending order :

257536, 38952, 385081, 365062

Sol. The smallest number is 38952. Other numbers greater than 38952, in order are 257536, 365062 and 385081.

*∴* The numbers in ascending order are 38952, 257536, 365062, 385081.

Ex: Arrange the following numbers in descending order : 19710, 887151, 453212, 925473

Sol. The greatest number is 925473. Other numbers smaller than 925473 in order are 887151, 453212 and 19710.

*∴* The numbers in descending order are 925473, 887151, 453212, 19710.]