Sorry about the previous errors in the code.

Could any one help with the numbering in the \overset or \underset in equations?

I need to add number above/below certain variables in the equations because I have so many variables. And the equations are very long. I consider to use the counter to auto-number the variables in equations. I tried the following code, but it seems that the \overset and \underset conflicts with the label of equation.

I got the following errors:

```
Package amsmath Error: Multiple \label's: label 'Eq1' will be lost. Y & = \overset{\dln{aaa}}{\boxed{a}}
```

Does anyone please help me with it. Thanks a lot. The code is here:

```
\documentclass{article}
\usepackage{amssymb}
\usepackage{amsmath}
\newcounter{rtaskno}
\DeclareRobustCommand{\dln}[1]{%
\refstepcounter{rtaskno}%
\thertaskno\label{#1}}
\begin{document}
Here is the equation:\\
\begin{equation}\label{Eq1} % I need the Eq. number
\begin{aligned} % I need the aligned equation
Y & = \overset{\dln{aaa}}{\boxed{a}} x_1 \\ % I need the aaa to be auto numbered
& + \underset{2}{\boxed{b}} x_2 % I need the bbb to be auto numbered
\end{aligned}
\end{equation}
Here is how to refer \dln{aaa}. % I need to refer the number indexed by aaa
\end{document}
```

## Best Answer