Moral dilema?

Conversation between Abby and Regan:

Regan: Mom I need help with my homework I don't understand this word problem on my math worksheet.

Abby: Okay lets read it aloud and work it together.

Regan: Susie wants to buy some candy and it cost 37 cents, she gives the cashier 50 cents. The cashier gives her 11 cents in change. Is this correct why or why not?

Abby: Okay I see you worked the problem out here you took 37 minus 50 and got 13. So that makes it incorrect right?

Regan: yeah so what am I supposed to put for why?

Abby: Well just put they subtracted incorrectly.

Regan: But WHY mom why would the cashier do that? Are they dishonest, are they trying to get away with something...why?

Abby: (pause) Regan I really don't think your math worksheet is asking for a moral dilema here. I could be wrong but what I think the teacher is looking for is just a plain he subtracted incorrectly.

Regan: Okaaaaay if you say so mom!