I am working in the Overleaf IDE, and simply trying to write down some fraction multiplications. As a simple example, let's consider the expression to be (a/b)(c/d).

Within my \begin{displaymath} environment, my code is this:

\frac{a}{b} \frac{c}{d}

Yet what comes out is a times (blank over b times (c over d)). Sorry if that's a confusing way of writing it. I've included a picture of the output. I've also tried writing the code with parentheses around the two fractions, but the same error occurs. I just want to write down some simple fractions, can anyone point out what might be causing this issue?


  • 1
    the input you show would not (with the usual definitions) produce the output you show. Please (always) include a complete small document that shows the problem. Jan 27, 2021 at 23:24

1 Answer 1


I would guess that you have



\frac{a}{b} \frac{c}{d}


enter image description here

You need to remove the blank lines.

Never ignore errors, Latex reports

! Missing $ inserted.
<inserted text> 

After any error the PDF is not intended to be usable. (a red circle on overleaf)

  • Yes, yes you are exactly correct. Thank you for the help.
    – taehyun778
    Jan 27, 2021 at 23:59
  • @DavidCarlisle Hi, truly I have thinked to \over like in LibreOffice or the old OpenOffice. I hope that you read my comment. Now I have removed my answer: I had not understood also the question. +1
    – Sebastiano
    Jan 28, 2021 at 11:51

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