conversations.from: human
conversations.value: Solve the math problem: Nate is reading a 400-page book. He finished reading 20% of the book. How many pages does he need to read to finish the book?
conversations.from: assistant
conversations.value: Nate had read 400 x 20/100 = 80 pages.
  So, he still needs to read 400 - 80 = 320 pages to finish the book.