=sum('Anonymous:Wyatt,Virginia'!f45:f45)

This is an excel formula adding F45 from all worksheets from anonymous to Wyatt (about 30) and returning the total, but will not work in Libre. Can someone help me?

Calc is much more consistent here: it defines first range cell, then last range cell, and both cells just use full address:

=SUM(Anonymous.F45:'Wyatt,Virginia'.F45)