Hi. Your question has one of three different answers, depending upon your transcription as a whole.
1. If this is a Nemeth transcription (if you are using the Nemeth Code throughout the book, volume, or chapter) then you follow Nemeth Code.
2. If this is a Literary Braille transcription and is for pleasure reading, follow EBAE Rule VII, Sec.28.j and substitute words for the common mathematical signs. In the example you have provided, rather than substituting "times" you would say "by" since this is how it would be read aloud.
3. If this is a Literary Braille transcription and is for use in a classroom, follow Braille Formats 2011 Guidlines 1.3.4, using the Begin and End Nemeth Code indicators, following Nemeth Code for the construction of the mathematical expression.
[simbraille]_% #2@*4 _:[/simbraille]