Defined combination of numbers and text

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13

From the file, I think you want the sum to just ignore the "+" sign.
image

You now have

coalesce(${megalithal_stufen}, '0') + coalesce(${makrolithal_stufen} , '0') + ...

I think it could be if the variable is "+" then use '0', else use coalesce(...):

if(${megalithal_stufen} = "+",  '0', coalesce(${megalithal_stufen}, '0')) + if(${makrolithal_stufen} = "+",  '0', coalesce(${makrolithal_stufen} , '0')) + ...

(check if() documentation)

Also, I think E17 and E18 can be empty (required column), I think you only need L17 and L18 (relevant)