I use Mathstackexchange frequently and usually I write down my question on Lyx and then copy to the website. However, I must insert a $ sign before and after every equation while I am writing it down with Lyx. Is there a smart way to do this without inserting it every time? Thank you. Here's how it looks like. As you can see I want to insert a $ symbol everytime.enter image description here

  • Welcome to TeX.SX! What do you mean? A keyboard shortcut, leaving it out completely?
    – TeXnician
    May 27, 2017 at 11:37
  • Thank you. Yes, exactly. I don't know if for example Lyx has some kind of built-in function that everytime I initialize an equation it would insert those "$" signs. As far as I know there's something called macros but I don't know if this would solve my problem.
    – aadcg
    May 27, 2017 at 11:44
  • Do you start all your equations the same way? How should Lyx know when math starts other than $? I do not really get it, but maybe there are some Lyx experts who can manage it. (Btw: Macros could also refer to TeX commands.)
    – TeXnician
    May 27, 2017 at 11:46
  • I don't know absolutely anything about Latex except using Lyx. When you want to insert an equation on Lyx you simple press CRTL + M. I will attach a photo to my post.
    – aadcg
    May 27, 2017 at 11:49
  • I don't get it either. I use LyX sometimes and in that case I don't need to introduce those $ myself. Entering math inline mode is enough (the CTRL+M shortcut you speak of). May 27, 2017 at 12:23

1 Answer 1


Sort answer: Ctrl+M already insert $ $ in LaTeX code.

Long answer:

In LaTeX $ is an active character that start/end the inline math mode. In Lyx, $ is not a active character that will do nothing except print that symbol, and it will we exported to LaTeX as\$ (the inactive symbol) in text mode or in math mode.

Therefore you cannot write in LyX $...$ to make an equation like in LaTeX, except if you are in a TeX box, aka Evil Red Tex (ERT), using Ctrl+L but then you must work with LateX code in the red box, that do not show anything except what you write. Be careful with ERTs, some typo here can produce a fatal error (= no PDF preview).

To write in math mode in LyX use the blue ∑ butttom or Ctrl+M. This make a blue box, warning you that a math environment equivalent to $...$ in LaTeX is already done, then you can write the equation with LaTeX commands as \simeq but is showed the correspondent symbol .

You can also write the equation "as is" in text mode (e.g.: A \simeq B), then select the equation with the cursor and use Ctrl+M to convert to math mode (i.e.,A≃B).

But as show your screenshot, all you equations are already in math mode, so you are trying is not only wrong, but also absolutely unnecessary.

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