Meanings

profit and loss account

familiarity with the land

final settlement

credit account

guess

balance (of an account)

bill or account payable

rough estimate

quick on the uptake

to settle one's account

to pay one's bill

to use one's intuition

open account

Dutch treat

splitting the bill so that the others end up paying the whole amount

profit-and-loss arithmetic

counting on the abacus

counting "stars" to tally the score to date

"winner" of a meal paid for by dutch treat (i.e. the person who eats the most)

"loser" of a meal paid for by dutch treat (i.e. the person who eats the least)