A Fortiori/Examples

Examples of Use of A Fortiori

Prime Number

The following is an example of a fortiori reasoning:

The number $11$ is a prime number.

Hence $11$ a fortiori is not divisible by $5$.

A Family Matter

The following is an example of a fortiori reasoning:

I am too old for this game; therefore, my father is also too old.

That is, the knowledge:

My father is too old for this game.

arises a fortiori from the stronger knowledge that:

I am too old for this game.