Treat this as an extra needed keyboard.
I m glad I came across it as I will keep a printed copy underneath my compter.
Important symbols for me are:
alt 3 = heart
alt 171 = 1/2
alt 174 = 1/4
alt 14= Loes musical symbol
alt 15= cents symbol
alt 251 = squuare root
alt 253 = square of
alt 227= Pi symbol
alt 228 = sum of (included integers) symbol
To build arrows -
alt 24 = up arrow
alt 25 = down arrow
alt 26 = right arrow
alt 27 = left arrow
This will be saved and close to my alt + 3 from now on!