conversations.from: human
conversations.value: Peter has 20 books. He has read 40% of them. His brother has read 10% of them. How many more of these books has Peter read than his brother?
  Can you solve this problem?
conversations.from: assistant
conversations.value: Peter has read 8 of these books because 20 x .4 = 8
  His brother has read 2 of these books because 20 x .1 = 2
  Peter has read 6 more books than his brother because 8 - 2 = 6