How to change the global font size of align?

Question

I'd like to change the font size of align blocks. I've tried to change it by using \large, but this also changes the equation numbering. The second approach was to use \declaremathsizes in combination with \everymath{\displaystyle} before the document starts. But this requires to use the command each and every time. I don't know why, but using the command didn't change the text at all. These are my code snippets so far:

style.sty:

...
\RequirePackage{amssymb, amsmath}
\DeclareMathSizes{20}{28}{22}{28} 
...

main.tex:

...
\everymath{\displaystyle}
\begin{document}
...
this is some random text to compare the font sizes between equations and normal text...

large
{\large
\begin{align}
    \hat{r}_{ui} &= r_{ui} - \bar{r_u} \\[10pt]
    \hat{r}_{ui} &= r_{ui} - \bar{r_u} 
\end{align} 
}%

normalsize
{\normalsize
\begin{align}
    \hat{r}_{ui} &= r_{ui} - \bar{r_u} \\[10pt]
    \hat{r}_{ui} &= r_{ui} - \bar{r_u} 
\end{align} 
}%

using \$ ...\$
$\hat{r}_{ui} = r_{ui} - \bar{r_u}$ \\

nothing specified
\begin{align}
    \displaystyle \hat{r}_{ui} &= r_{ui} - \bar{r_u} \\[10pt]
    \hat{r}_{ui} &= r_{ui} - \bar{r_u} 
\end{align} 

I've just found this etoolbox This changes the font sizes everywhere but doesn't seem to be recommended.

Answer 1

\DeclareMathSizes{12}{14}{10}{8} solved it. Make sure that the first parameter is equal to your used standard text font size.