L: So Mom, are you and Dad going to buy my phone? Konsola wants me to get it this weekend.
M: No, both Dad and I understood that if you were good for a week, that you'd have the privalege of having a phone, but you would have to buy it.
L: But Mom, it's only on sale this week. And it's only $100.
M: If it's only $100, then you buy it.
L: But I don't have the money.
M: Neither do we.
L: If I had a job, I could earn $100 just like that.
M: Okay, so if you made $4 an hour, how long would it take you to make $100?
L: (gets the calculator out and calculates) 25 days.
(then relays the conversation to her friend on the phone and re-calculates ....
It would take me 25 hours a day for 4 days to earn $100.
(Mom exits kitchen hiding a very broad smile and chuckling under her breath.)