Mother: So, you're coming here at the beginning of September and when do you leave?
Me: The 20-something.
Mother: Of September?
Mother: Well, when exactly?
Me: The 20-something - I need to decide when
Mother: When do you need to be back?
Me: 1st October.
Mother: How many days does September have?
Mother: 30 days has September, April, June....oh yes, 30.
Me: Yes, 30.
Mother: So you could go back on the 30th?
Mother: You could go back on the 30th?
Me: Yes, Mother, I could go back on the 30th.