JSFiddle - React, Tailwind, and code Playground
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<script src="https://polyfill.io/v3/polyfill.min.js?features=es6"></script>
<script id="MathJax-script" async src="https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-mml-chtml.js"></script>
\[\sigma_{\tiny X}^{2} = VAR[X = E[(X-m_X)^2]\]
\[\sigma_{\scriptsize X}^{2} = VAR[X = E[(X-m_X)^2]\]
\[\sigma_{\footnotesize X}^{2} = VAR[X = E[(X-m_X)^2]\]
\[\sigma_{\small X}^{2} = VAR[X = E[(X-m_X)^2]\]
\[\sigma_{X}^{2} = VAR[X = E[(X-m_X)^2]\]
\[\sigma_{\large X}^{2} = VAR[X = E[(X-m_X)^2]\]
\[\sigma_{\Large X}^{2} = VAR[X = E[(X-m_X)^2]\]
\[\sigma_{\LARGE X}^{2} = VAR[X = E[(X-m_X)^2]\]
\[\sigma_{\huge X}^{2} = VAR[X = E[(X-m_X)^2]\]