Page rules apply to the entire zone (domain and subdomains).
You can wildcard Page Rules to match all sub & domains: *example.com/path/*
Or you can specify a hostname: example.com/my/file.php (won’t match subdomains).
The way you specify your paths means you’ll need multiple rules because the paths are unique.
No page rule will precisely match foo.com/a/ and sub.foo.com/b/