This new question has given me an idea.
The numbers, seen as nouns, are feminine (die Eins, die Null, usw.). This can be thought of as if they were "inheriting" the gender of their collective, die Zahl
die (Zahl) Eins, …
(one understandable exception to the rule being π, das Pi).
That doesn't happen for each object. For instance, the following "deduction" is false
der Buchstabe demzufolge ist der (Buchstabe) A ← (falsch!)
for the correct gender for letters is neutral. But something makes me think that this is rather an exception to the rule with the numbers above.
Example:
- Ich habe eine Krakauer und ein Paulaner gekauft. Dannach habe ich auch einen Berliner gegessen.
The genders come from die Krakauer-Wurst, Paulaner ist ein Bier (das) and from der Berliner-Pfannkuchen, but Wurst, Bier and Pfannkuchen are tacit)
Question: Is there a rule that generalizes these examples? That is, a rule that allows us to apply the same gender of a tacit noun to its particularizations.