The paintings featured in the film are: "Woman with Parasol and Child" by Pierre-Auguste Renoir, 1874; "A Friend in Need" (Dogs Playing Poker) by Cassius Coolidge, 1903; and "Free Form" by Jackson Pollock, 1946.
While for dramatic effect, the script calls out the repeated use of the number "three" as an indicator of fraudulent numbers, the theory behind fraudulent number detection is known as "Benford's Law." The law states that in numbers, such as account transactions, the probability of a number occurring naturally drops, as one moves from smaller numbers to the larger numbers following a logarithmic scale. This law has been successfully used to detect fraudulent accounting transactions.
Anna Kendrick based her character on her mother, a real accountant who went over the script and explained the math to her daughter.
"Where fun goes to die" is an actual unofficial motto of the University of Chicago.
In the hotel room, Dana (Anna Kendrick) reveals that in order to get the money to buy a Vera Wang gown, she taught herself how to play blackjack and to count cards to determine the chance to win a hand. In real life, Ben Affleck is known to be such a cunning poker and blackjack card player that he has been barred from several casinos. Not because he cheats, but because of his well-known habit of card-counting. Legal, but against casino rules.