The subset of the real numbers \(\mathbb{R}\) that can be expressed as \( \frac{1}{144} \) is simply the single number \( \frac{1}{144} \).
In set notation, this can be represented as:
\[ \left{ \frac{1}{144} \right} \]
If you are asking about the broader context in terms of all real numbers that are rational or any specific subset related to \(\frac{1}{144}\), please provide additional details!