The consensus from the committee is in!
Braille Formats 2016 is our source for this formatting issue. In an exercise format of 1-5, 3-5, we should format displayed math expressions in 7-9 with space before and after, per BF2016 §10.7.
Our understanding is that a format of 7-9 allows the braille user to most easily pinpoint the beginning of the expression (or beginning of each expression if there were more than one).
🤓 Further citation: The second paragraph under 3. General format (GTM 1.4.1) in BANA's Provisional Guidance on Transcribing Mathematics in UEB says,
Follow Braille Formats: Principles of Print-to-Braille Transcription, 2016 for the format of displayed literary text except for paragraph format, which is never blocked. For displayed mathematical expressions, use blank lines preceding and following; and indent 2 cells from the runover position of the material to which they apply.
Please let us know if you need something more or different!