Final answer:
The question calculates the number of members in a Tahitian household. A detailed population count is given, but without a clear definition of a 'household' in Tahitian culture, the exact number of 'letters' or members per household cannot be provided. The calculation relates to understanding societal structures in the Austral Islands of French Polynesia.
Step-by-step explanation:
The question concerns the calculation of the number of members in a Tahitian household, taking into account a population summary that includes specific details about the individuals by gender, age, and status within the community. The details are essential to determine the composition of the households and understand the demographic structure of the population in the context of the Austral Islands which, as part of French Polynesia, have economic activities centered around black pearls and coconuts.
By assessing the provided details, we count the individuals in each category: 31 (30) able-bodied male adults, 5 helping sons, 2 additional sons, 5 small sons, and 1 elder among males; 45 able-bodied female adults, 4 helping daughters, 13 additional daughters, 9 small daughters, 1 exempt mother, and 1 elderly mother among females. Including the 7 persons who moved in, we come to a total of 125 individuals in the community.
Since the nature of Tahitian households, their formation, including the sujwanae hearth, is specific to the practices and definitions within the Tahitian culture and can vary widely, the precise number of letters or members per household can't be provided without further context regarding the definition of a Tahitian household's structure and the grouping of individuals.