After the children receive the disappointing letter informing them that the museum already knew all about the mark on the bottom of the statue, Claudia breaks down and weeps. She then reveals how determined she is to find out the truth about the statue. Jamie is rather puzzled by her behavior, and makes the comment below. Claudia is indeed a high-strung and demanding person, who demands perfection in herself and others; this is encompassed by her trait of wondering where the pluses are when she gets A's. Jamie's assessment of Claudia's character is strengthened by her correction of his bungling of Florence Nightingale's name. However, like her comment to Jamie previously, this is not entirely correct: Claudia is relentless when pursuing a goal, but she is ultimately satisfied when she finds out the truth about Angel.
You’re never satisfied, Claude. If you get all A’s, you wonder where are the pluses. You start out just running away, and you end up wanting to know everything. Wanting to be Joan of Arc, Clara Barton, and Florence Nightingown all in one.” “Nightingale,” Claudia sighed. She got up then and followed slowly behind her brother.
Pg. 121