I suggested a synonym 'formulas' → 'formula'. Please vote.
I think that for consistency, we should have tags in plural form. Another way to think about it, is to fill in the blank:
This question is about <tag-name>.
For this reason, I think
[formula] should be merged into
Note: for some of the other synonyms I suggested, I wasn't able to choose the plural form as the master tag, so I chose the singular form. Once one of these have been approved, I would recommend that a mod change it to its plural form for consistency.
It's a good spot anyways, so thanks for the suggestion. One other thing to note is that only 5 of us at the present time have enough reputation (2500) to vote on the synonyms.