Multiplicative Group of Rationals is Normal Subgroup of Reals

Theorem
Let $\left({\Q^*, \times}\right)$ be the Multiplicative Group of Rational Numbers.

Let $\left({\R^*, \times}\right)$ be the Multiplicative Group of Real Numbers.

Then $\left({\Q^*, \times}\right)$ is a normal subgroup of $\left({\R^*, \times}\right)$.

Proof
From the definition of real numbers, it is clear that $\Q$ is a subset of $\R$.

As $\left({\R^*, \times}\right)$ is a group, and $\left({\Q^*, \times}\right)$ is a group, it follows from the definition of subgroup that $\left({\Q^*, \times}\right)$ is a subgroup of $\left({\R^*, \times}\right)$.

As $\left({\R^*, \times}\right)$ is abelian, it follows from All Subgroups of Abelian Group are Normal that $\left({\Q^*, \times}\right)$ is normal in $\left({\R^*, \times}\right)$.