Numbers are of various types, such as natural numbers, prime and composite numbers. Chapter 3 completely focuses on Whole Numbers and their important properties. In Mathematics, whole numbers are nothing but the basic counting numbers 0,1,2,3, and so on. Whole numbers also include the natural numbers that begin from 1. It includes all positive integers along with 0. Every number has its predecessor except 0, and all the whole numbers have successors.
For example, the successor of 0 is 1, and the predecessor is -1, but negative integers are not included in whole numbers. Thus, there does not exist any largest natural or whole number. However, operations like finding ascending and descending order, determining the larger number among the two using > and < can be performed on whole numbers. Furthermore, whole numbers between two numbers can be determined by the difference between the two and subtracting 1. For example, the whole number between 31 and 71 is 40-1=39.
Whole numbers, when added or multiplied, result in a whole number, whereas in the case of subtraction, it can be an integer too. Whole numbers obey closure property, commutative property under addition and multiplication. The additive identity of any whole number is 0, and their multiplicative identity is always 1.
The Chapter finally talks about a few important properties that need to be considered. The most important property of whole numbers is if a and b are whole numbers, and if a < b, then a+1 is also lesser than b+1, i.e. a+1 < b+1. It also talks about an important rule that the product of a whole number and its successor is always an even number.
The students must understand this chapter thoroughly as it holds great weightage from an exam point of view and in the chapters that follow. Moreover, the chapter teaches many small points, tricks to solve arithmetic maths dealing with practical problems.