The phrase "did a number" usually means to cause some kind of damage or disruption. The antonyms for this phrase would be words that imply repairing or improving something. Such words could include "fixed," "repaired," "restored," "healed," "ameliorated," or "mended." These words all suggest a positive outcome or progress, the opposite of the negative consequences implied by "doing a number." It is important to keep our language balanced and nuanced, and using antonyms such as these can help us do just that.