Thank you for following up and clearing things up.
In response to your question, a tactile graphic would likely give the most clear representation of a broken number line. However, if you must use braille cells, I would suggest the configuration in the image attached (in which slashes are used to represent the break in the line) paired with a transcriber's note stating something to the effect of "diagonal slashes / indicate a break in the number line" (It would be ideal to use wording from the video you mention).
Thank you again for your question. And keep on rocking the transcription!