Mathf not working

Hey guys, I’m new to unity and C#, and I found so many tutorials talking about Mathf, when I tried using it, it didn’t work or even appear in a different color in visual studio, I searched everywhere and I couldn’t find anything, can you help?

You need to set VS in the external tools tab.

Edit>Preferences>ExternalTools>ExternalScriptEditor and then press Regenerate project files.

If you need a picture to find it:

Post a screenshoot of visual studio, just after creating a script