conversations.from: human
conversations.value: Joy has 250 feet of tape. She wants to wrap the tape around a field that is 20 feet wide and 60 feet long. How much tape will Joy have left over after wrapping tape around the field once?
  Give me a clear explanation.
conversations.from: assistant
conversations.value: The perimeter of the field is 20+20+60+60=160 feet.
  Joy will have 250-160=90 feet of tape left over.