**My question** I toggle elements between beamer and article (again...). This time I'd like have a correspondence between a `marginnote` of just one `equation` in `article`, and a `frame` with the same equation, but scaled to `\textwidth` **What I already read** https://tex.stackexchange.com/questions/38352/resize-scale-equation-in-beamer and https://tex.stackexchange.com/questions/448654/automatically-resize-equations based on the last one for MWE. It works in `article`, not in `beamer` (missin $ inserted error :/) ![TAEquationsidenote.png](/image?hash=df460d2cd094a907f6e82d82e1e26066d5586bf5bedd0a42247c89647a29704c) ![TAEquationsidenote2.png](/image?hash=c500a85ed69c2cf58012bb2cee9735a950a9282d317cb9c190092b75667d52fe) **MWE** ``` \documentclass{beamer} %\documentclass{article} %\usepackage{beamerarticle} \usepackage{graphics} \usepackage{mathtools} \usepackage{comment} \usepackage{lipsum} \begin{comment} \usepackage{sidenotes} \usepackage{marginnote} \DeclareCaptionType[fileext=eqn]{equa}[Formule][Formules à retenir] \usepackage{geometry} \geometry{ a4paper, top=2cm, bottom=2cm, left=15.00mm, textwidth=130mm, marginparsep=8.2mm, marginparwidth=50.0mm } \end{comment} \newcommand{\hackEq}[2]{ \mode<article> {%Sidenote with equation \marginpar{\captionof{equa}{#2} \[#1\] } } \mode<beamer>{%slide with one centered big equation \begin{frame} \frametitle{#2}% \begin{equation*} \resizebox{.9\textwidth}{!}{#1} \end{equation*} \end{frame} } } \begin{document} \begin{frame} \frametitle{Title} \lipsum[1] \end{frame} \hackEq {% \displaystyle R=\frac{\sum_{i=1}^{m}\left(F_{i}+s\right) t_{i} D_{i}}{\sum_{i=1}^{m} \tau_{i} D_{i}} }% {Equation Name or very short sentence.} \end{document} ```

The problem is (besides a missing `{`) that the content of `\resizebox` is back in text mode, you can fix this by wrapping your argument in math mode. (the `equation*` environment around is then not really necessary any more, you could replace it with centering) ``` \documentclass{beamer} %\documentclass{article} %\usepackage{beamerarticle} \usepackage{lipsum} %\usepackage{sidenotes} %\usepackage{marginnote} %\DeclareCaptionType[fileext=eqn]{equa}[Formule][Formules à retenir] \geometry{ a4paper, top=2cm, bottom=2cm, left=15.00mm, textwidth=130mm, marginparsep=8.2mm, marginparwidth=50.0mm } \newcommand{\hackEq}[2]{ \mode<article>{%Sidenote with equation \marginpar{\captionof{equa}{#2} \[#1\] } } \mode<beamer>{%slide with one centered big equation \begin{frame} \frametitle{#2}% \begin{equation*} \resizebox{.9\textwidth}{!}{$\displaystyle #1 $} \end{equation*} \end{frame} } } \begin{document} \begin{frame} \frametitle{Title} \lipsum[1] \end{frame} \hackEq {% \displaystyle R=\frac{\sum_{i=1}^{m}\left(F_{i}+s\right) t_{i} D_{i}}{\sum_{i=1}^{m} \tau_{i} D_{i}} }% {Equation Name or very short sentence.} \end{document} ```