Theory:

Ajay's father asked him to count how many guests are arrived at his home. Then Ajay started counting \(1\), \(2\), \(3\), \(4\) and he finished with the number \(10\).
 
Do you know why did he start to count with \(1?\) Because natural numbers start from \(1\).
 
But what about whole numbers?
 
We include zero in the whole number system. So all the natural numbers come inside in the whole number system.
 
Therefore we can say that all the natural numbers are the whole number. But are all the whole numbers are natural numbers? Think about it.
 
Now let's see the definition of whole numbers.
Whole number:
The number system which includes all the positive numbers along with zero forms the collection of whole numbers.
All-natural numbers are whole numbers, but not all whole numbers are natural numbers because, in the whole number system, zero is included but not in the natural number system.
We learned about the whole numbers now we take a look into predecessor and successor.
Predecessor:
  • The predecessor is the word that refers to the earlier place, object, or person from the reference point or a number.
  • The predecessor means previous.
Example:
In the Indian cricket team, Mr. M.S.Dhoni is the predecessor captain of the Indian cricket team before Mr. Virat Kohli. That is Mr. M.S.Dhoni was the Indian cricket team captain before Mr. Virat Kohli.
Similarly, in the number system, we can say that \(5\) is the predecessor of \(6\).
 
We can get a predecessor for any number by subtracting the number by \(1\)
 
In the above, it is mentioned that \(5\) is the predecessor of \(6\), we get predecessor of \(6\) when subtracting it by \(1\).
 
That is 61 \(=\) 5.
 
Therefore, to find the predecessor of a particular number, we have to subtract the given number by \(1\).
 
Successor:
The successor means the next one from the reference point or number.
Example:
i) Mr. Virat Kohli is the successor captain of Mr. M.S.Dhoni in the Indian cricket team.
 
ii) If you're taking responsibility for your house after your father, then we can say that you're a successor of your father.
In the number system, we can say that \(4\) is the successor of \(3\). But how do we get it?
 
To get the successor of the particular number we have to add the given number with \(1\).
 
That is 3+1 \(=\) 4.
 
Therefore, to find the successor of a particular number, we have to add the given number by \(1\).