Hi, I use #maths in my tags, but it is the British English abbreviation, so putting it as the lead tag will not get as many readers as #mathematics and #math, the US abbrev.
However, when I asked @jesta for the Mathematics Forum to be created on chainBB, it was coded so that any of the 3 obvious tags as the lead tag would qualify for insertion in that forum.
So, if you go to: https://beta.chainbb.com/forum/math (you will need to sign in if not used before) you will see your post in there, even though you used #maths. That's the smart way of doing tags, directing synonyms to the same place.