I believe it's an "a" with a dash though it.
Before a symbol. Not sure about a formula.
Quotation marks should come before and after a symbol.
we use the best before symbol because we know when we can eat and when it goes rotten
There was no symbol prior to the donkey.
The euro symbol goes after.
The symbol was NSCP before it was bought out by AOL.
The symbol of Aphrodite is the female symbol. Keep in mind as well, that the female symbol was Aphrodite's symbol before it was the female symbol.
The symbol used before a number to make it a label is a hash sign (#).
It goes before the number
The @ symbol you mean? If you want to tag them in it, yes.
a colon is used before a list, this symbol :
after