conversations.from: human
conversations.value: Madeline spends 18 hours a week in class. She spends 4 hours per day working on homework. She spends 8 hours per day sleeping. She works part-time 20 hours per week. How many hours left over does Madeline have?
  Can you solve this problem?
conversations.from: assistant
conversations.value: Madeline spends 4*7=28 hours on homework.
  She spends 8*7-56 hours sleeping.
  Therefore, she is busy 28+18+56+20=122 hours per week.
  There are 7*24=168 hours per week.
  Thus, Madeline has 168-122=46 hours left over.