### Theory:

A number comes before a number is called a predecessor and a number comes after a number is called a successor.
Rule for getting predecessor and successor:
• Add $$1$$ to a number to get the successor.
• Subtract $$1$$ to a number to get the predecessor.
Example:
1. Consider the number $$16$$.

$$15$$ comes before $$16$$. So $$15$$ is the predecessor of $$16$$.

$$17$$ comes after $$16$$. So $$17$$ is the successor of $$16$$.

Verify: Add $$1$$ to $$16$$. $$16+1 =17$$ - successor of $$16$$.

Subtract $$1$$ to $$16$$. $$16-1=15$$ - predecessor of $$16$$.

2. Consider $$99999$$.

$$99998$$ comes before $$99999$$. So $$99998$$ is the predecessor of $$99999$$.

$$100000$$ comes after $$99999$$. So $$100000$$ is the successor of $$99999$$.

3. Predecessor of smallest $$5$$ digit number.

The smallest $$6$$ digit number is $$10000$$.

Subtract 1 to a number to get the predecessor.

Predecessor of $$10000 = 10000 - 1 = 9999$$.