答案1
简单地嵌套cases
环境:
\documentclass[12pt,a4paper]{article}
\usepackage{mathtools}
\DeclareMathOperator{\rand}{rand}
\begin{document}
\[ \begin{cases}
a = 5\\
\begin{cases}
\text{Noise} = (\text{MaxValue}-\text{MinValue})*\rand(1)+\text{MinValue}\\
k=k+1
\end{cases}\\
a = a + 5
\end{cases} \]
\end{document}