# Math font in beamer class in LyX

How do I get LMR or CMR math font in beamer class in LyX? In the document settings when I change the font only the text is affected and not the equations.

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`bemear` uses CM by default: you must be making some font changes to get a different font in the first place. – Joseph Wright Jan 4 '13 at 7:09
@JosephWright I already tried the default settings. I still don't get CMR – PhHEP Jan 4 '13 at 7:17
Ah, you want the `serif` option. I'll post an answer, but as it's for 'standard' LaTeX there may be more to say for Lyx. – Joseph Wright Jan 4 '13 at 7:27

``````\usefonttheme{professionalfonts}
into the "Document->Setting->LaTeX preamble", then `beamer` didn't change anything in the math fonts