Answer:
A rational numbers can be defined as numbers that can be expressed as the quotient between two integers.
This means that a whole number can be expressed as a rational number by just adding 1 into its denominator
![2 \implies (2)/(1)](https://img.qammunity.org/2020/formulas/mathematics/middle-school/rdweg0r7nxm0328prq11st4j1d39djl6cm.png)
That way the whole number would be a rational number, becase 2 and 1 are integers.
Therefore, an expression can be written in rational form by writing it as a fraction with a denominator of 1.