Adding values from a named list

I have a sheet of resistors, names in one column and value in an other column, it is possible to lookit up with VLOOKUP or HLOOKUP but I should like to get the values automatic added from a list of resistor names.

Sheet 1: list of resistor names and its value; Sheet2 a column given a list of resistor names and a field there the resistors is added up. Say “R1+R2+R342+A34” and its value it’s added up, other formula should work also if operator is possible,
operator @ as VLOOKUP and given tables of names and value. “@R1+@R2+@R342+@A34”
More complex “”@R1//@R2" there R1 and R2 resistors are in parallel recording formula R=1/(1/R1+1/R2) there // is an other operator. Now I don’t know if that is working in any languages or exchange @ and // with SER(R1,R2) och PA(R1,R2) there SER o PAR is working more as a function.

Its little hard to explain.

You can assign names to the values selecting the columns used for VLOOKUP and creating the range names with Menu/Sheet/Named range or Expressions/Create - Left. Then it’s possible use those names in the cells for calculations.

LibreOffice Calc Guide chapter 13 - Associating a name with a range.