The low number appears to be hardcoded into the software. At least I did not find the setting.
Same about the one line. I would like to expand, but I am not sure it is possible.
I have not tried all kind of [ x ] tags, in the input. Doing so would always be public to all.
There are a number of addons to smf. I do not know how efficient they are. And I need to request them to be installed by the server admin (not me). Also they may need testing before....
I did some investigating, I can add color and [ br ] works. (I still have to edit all into one line...)
I reworded the question.....
Still waiting to learn what is ambiguous in the prime number question
New screenshot attached.
--- EDIT
I changed the text to "the red letters in the next line"
I case someone's browser wraps text
Also "Pick and add all "prime numbers": 23,10,4,33,3,4,9,13 then add them together"