Half the population is male.
This village's population is only 23.
Many Japanese people don’t know the population of their own town.
The amount of people with mouths (that you have to feed) is the population that you have to feed.
Both kanji in this jukugo (combo kanji) use the on'yomi readings that you've already learned! So just make sure you know those and you'll be able to read this too.