The successor of a two-digit number is always a two-digit number.
Try to find the example which does not follow this statement
The successor of a two-digit number is always not a two-digit number.
Let's consider a two-digit number .
The successor of a number is the number obtained by adding to it.
.
So, the successor of is , which is a three-digit number.
Therefore, the successor of a two-digit number can be a three-digit number.
Hence, the given statement is false.