math equation are displaying wingdings for symbols [SOLVED]

[JohnWeak]

so I’ve been writing math equation on libreoffice to write my math lessons but at some point when I opened text document with math equations I realized this

I don’t know how to fix this and I need help

edit : I use window 10 and this is a .odt

thanks in advance

[mikekaganski]

Looks like missing OpenSymbol font

[ajlittoz]

And to complicate matters, you don’t tell your OS nor how you saved your file (.odt or .doc(x)).

[JohnWeak]

ok I’ve searched for open fonts online and found it. So I downloaded it and installed it
thanks