This message can be caused by a number of errors:
- You might have missed the beginning of one of the mathematics
environments (that is, you've used a
command that must only appear in maths mode).
- You may have typed $ instead of \$ (you
actually want a dollar symbol to appear). Recall from
§4.3. Special Characters and Symbols that if you
want a $ sign to appear you need to do \$ not just $.
You would have got this error message if you had done, say,✘
expenditure came to $2000.00
expenditure came to \$2000.00
- You may have missed the end of a mathematics environment, or you may have a paragraph break within an in-line or displayed maths environment, where it is not permitted. Make sure you don't have any blank lines within the environment. If you want a blank line in your code to make it easier to edit, try having a percent sign at the start of an empty line to ensure that the line is ignored by LaTeX. For example:
This book is also available as A4 PDF or 12.8cm x 9.6cm PDF or paperback (ISBN 978-1-909440-00-5).