I must change my response!
In fact, the numeric-mode-initiated grade 1 is terminated by a line break. See the clarification of this rule in #5 of the “Provisional Guidance on Transcribing Mathematics in UEB” (quoted below).
Note that, in the case of an expression that is divided over more than one line, the end of a braille line counts as a braille space unless the dot 5 continuation indicator is used.
Nonetheless, a line continuation indicator (dot 5) is not most appropriate here, because it is clear that your runover line is a continuation of the expression that started on the previous line. To use a dot 5 continuation indicator would be overkill and probably confusing for the braille reader.
So, for the print in your first post, I would now recommend the following transcription as being the most accurate and easy-to-read.
⠰⠰⠰⠷⠭⠔⠼⠃⠐⠖⠼⠑⠭⠐⠖⠼⠙⠨⠌⠭⠔⠼⠃⠐⠖⠼⠋⠭⠐⠖⠼⠓⠾
⠀⠀⠐⠌⠷⠭⠔⠼⠃⠐⠖⠼⠃⠭⠐⠤⠼⠁⠑⠨⠌⠭⠔⠼⠃⠐⠤⠭⠐⠤⠼⠋⠾⠰⠄
–Kyle