Question

What is the difference between the decimal forms of rational numbers and the decimal forms of irrational numbers?

Answer 1

The decimal forms of rational numbers can be finite, i.e. have a non infinite number of digits. In case they have infinite digits then these are periodic. This means that there's a patron of digits that is repeated infinitely.

Irrational numbers on the other hand can only have infinite digits on their decimal form and they are not periodic.