The set of whole numbers is the set of natural numbers along with zero. so W = the set of whole numbers = 0,1,2,3,............
so Zero is the least number of the set of Whole numbers.
As the whole numbers is an infinite set we cant determine the highest number of this set.
The set of Whole numbers is a subset of Rational numbers.The best way to learn about whole numbers is to understand its properties,the properties of whole numbers are,it is advisable to use a number line inorder to understand the properties of whole numbers.
1. Number 3 <>
2. There is no whole number to the left of zero on the number line.So zero is the smaller number than each of the numbers to its right on the number line.That means 0 is the smallest or least of the whole numbers.
3. A whole number which is greater than a given whole number by 1 is said to be a successive whole number. 1 is the successive whole number to 0.Every whole number has one successor.
4. There is no whole number left to zero.hence 0 is not a successive whole number of any whole.
Hope you like the above example of Whole numbers.
Please leave your comments, if you have any doubts.

In the figure given above we can see the AC is called a Hypotenuse of the triangle and AB is called the opposite side of the triangle and BC is called the adjacent side of the triangle. This is the Pythagorean Theorem. It generally frames as

