Should it be written how many cares?

It seems like there might be a typo in your question. If you're asking whether to specify how many "cares" (perhaps referring to "cares" in a context like "how many people care"), it depends on the context. Providing a specific number can add clarity or emphasize the importance of an issue. However, if the term is more qualitative, describing the level of care might be more effective than quantifying it.