How to use \simeq in equation?

Question

I need to use \simeq in an equation, but my code is not workin':

\begin{equation}\label{m-step}
P(t) \simeq {\sum_{g\in G} {\sum_{f\in F} P(t|f,g)
\end{equation}

Can you tell me why?

Answer 1

You have some unnecessary braces before the \sums. Remove these and it works fine.

\documentclass{article}
\begin{document}
\begin{equation}\label{m-step}
P(t) \simeq \sum_{g\in G} \sum_{f\in F} P(t|f,g)
\end{equation}
\end{document}