You can change the way Text Speaker pronounces arithmetic words and symbols in your document.

On the Pronunciation dialog, enter the ‘-’ sign in the Word text field and put the word ‘minus’ in the Pronunciation text field. Test the pronunciation and click apply.

Now, if you start reading the document it will read the minus sign. Similarly, you can adjust the pronunciation for other arithmetic symbols. Once you finish adjusting the pronunciations, just convert the document file to audio format.