an addition / of a number, being positive / a plus, a benefit, a gain, an asset

plus, an operator in arithmetic

add

(adverbial particle, dismissive, derogatory) emphasizes disgust, contempt, or otherwise negative feelings of the speaker: whatever

question, problem on homework etc. / a question; a matter (of time etc.) / a problem (something that needs to be dealt with); a trouble / an issue; a matter

to grumble (about something trivial)

What? What did you say?

whatchamacallit, X

four, 4

(mahjong) four, 4