# How to refer to a group of equations in html/Mathjax

I am using MathJax on my website. When I refer to a single equation with label, the number turns out correct. However, when I write a group of equations like below,

\label{equation-example} \begin{aligned} A &= B + C \\ &= D \end{aligned}


the number reference somewhere else displays Eq (???). On the other hand, when I write a group of equations like below,

\begin{aligned} A &= B + C \\ &= D \end{aligned}\label{equation-example}


the number referencing is correct (e.g., Eq (4)). I know that  is from Tex and shouldn’t be encouraged. This code looks like a bad practice anyway.

What is the proper way of referring to a group of equations in html/MathJax?