It just happened to me, where I added a "-word" term to narrow it down and the number of results increased somehow. That means that they're doing something behind the scenes that's not as simple as "remove all results that contain "word".
I work for Google Search. Yes, totally agree, it's weird when the count goes up. It's something I hope we can fix. But it's not because we ignored the - symbol. It's because the counts are very fast, rough estimates. And when you go into additional pages, we start to refine them. IE: we actually found more than the count displayed on the first page.
A tangent. You have what I imagine is a hard job and, despite the many threads here about recent apparent quality decreases, the product brings enormous value to its users.
Thanks for taking the time to discuss in this thread, it is very helpful to see your insights.
Thank you. Forum discussions here and in other places are really useful ways to gather feedback. It directly drove the improvement we launched this week.
The "number" of results doesn't mean anything beyond a rough guess. it's an ad promlting the size of the index. You'll never be able to reach nearly all of them.