In the Provisional Guidance, Basic Guidance on when to Switch, it says, “Any mathematical or chemical formula should be done in Nemeth Code. This includes fragmentary expressions, including isolated signs of operation or comparison when mentioned in reference to such formulas.” And it also says, “A mere mention of a number or a letter variable within an otherwise UEB context should be done in UEB. This ‘number’ exception applies to both Arabic and Roman numbers and includes numbers that contain commas and decimal points, but not fractions, which should be done in Nemeth code.”
The question that has arose for us is, does one put numbers with their sign of operation (positive + and negative -) in Nemeth? This is what I have been doing, as they are signs of operation and are done differently in Nemeth than in UEB.
I have been treating them as one would an isolated sign of operation. I believe this to be correct as the “mere mention” rule does not say anything about a number with a sign of operation, but the rules do say to treat even fragmentary expressions and isolated signs of operation as Nemeth. Furthermore, it maintains consistency throughout the book for math symbols.
I submitted a similar question on 7/14/15 and was told that, "math notation refers to material that is presented differently in Nemeth Code than it is in UEB. And such material should be transcribed in Nemeth mode whether it appears alone or in the midst of an equation or expression.” I am assuming that this is the case in this situation as well.
Am I correct? Or would such positive and negative numbers, when alone, be considered a mere mention?
I have provided some examples: Page 168, exercises 15 and 17, and the table in Part 3.
I need to add an addendum/clarification to this answer. Originally, the guidance about numbers with a + or - in front of them did not say they had to be done in Nemeth. A change was made to the guidance that was recently updated and approved by BANA making it clear that any number that is modified mathematically (meaning it has a +, - or even a $ or %) should be done in Nemeth when using the Guidance for Nemeth in a UEB context. If these types of numbers come up in a literary text, they can be done using UEB symbols.