conversations.from: human
conversations.value: Leo has to write a 400-word story for his literature class. 10 words fit on each line of his notebook and 20 lines fit on each page. Lucas has filled one and a half pages. How many words does he have left to write?
  Give me a clear explanation.
conversations.from: assistant
conversations.value: Half a page is 20 / 2 =10 lines.
  In total, he has written 20 + 10 = 30 lines.
  The 30 lines written are 30 * 10 = 300 words.
  Lucas has 400 - 300 = 100 words left to write.