LaTeX LaTeX - dfrac with textstyle numerator

[Whovian]

While typing up a LaTeX document (long story,) in an align environment, I ran into having to type up a fraction which, while it didn't force the align to go off the page, it went past the later \tag{1}, which, needless to say, is somewhat annoying. I came up with the clever idea of limiting the fraction's size by using \tfrac, though this looked pretty annoying. So I came up with the other clever idea of only making the numerator \textstyle, which my intuition says will look lovely. Unfortunately, any attempt at doing so fails. For instance,

\dfrac{\textstyle a}{a}

parses to $\dfrac{\textstyle a}{a}$. Anyone have a solution to this, or, alternatively, another solution to my original problem?

 

[Zoli]

If I understand well, you want to make the counter smaller than the denominator. It can be done winthin an inline environment as eg.

Let us see the following equation: $\frac{a}{\displaystyle a}$