The natural numbers are the basis of all of mathematics.
To create a natural number we can write:
Another way to write the same thing, which involves less bracket matching is:
For convenience we can also just write the number as a decimal and it will convert it to a natural number.
We can multply two natural numbers together:
Equality:
Internal Representation
For speed and efficiency, the internal representation of natural numbers is not S(S(S(S(...0)))) but uses machine arithmetic.
$$\sqrt{1}$$