The Supplemental Mathematical Operators block spans U+2A00–U+2AFF, 256 codepoints in Plane 0 (Basic Multilingual Plane). Every one of them is assigned in Unicode 16.0.
All of its characters have the script value Common: they are shared across writing systems rather than tied to one.
By general category: 256 math symbols (Sm).
The first 256 arrived in Unicode 3.2 (2002).