There is an instruction on this page on how to tighten a bolt on a Chevy Sonic: http://www.csmans.com/engine_mount_bracket_installation-2169.html
It says tighten to 60 Y (45 lb ft) + 45?E0°
Now I can understand 45 lb ft and can convert that to nm which is what I'd use.
But what does all the rest mean? 60 Y and 45?E0°
If I already have the nm value, do I need to be weary about these other values?