The predecessor of a two digit number cannot be a single digit number.

If $a$ and $b$ are natural numbers and $a<b$, than there is a natural number $c$ such that $a<c<b$.

If $a$ and $b$ are whole numbers and $a<b$, then $a+1<b+1$.

The whole number $1$ has $0$ as predecessor.

The natural number $1$ has no predecessor.

The smallest natural number is:

The smallest whole number is

The predecessor of $1$ in natural numbers is