conversations.from: human
conversations.value: At least a third of Fred's marbles are dark blue. All of the rest are red, except for 4 that are green. If he has 63 marbles, how many of them are red?
  How to solve this?
conversations.from: assistant
conversations.value: Fred has 63/3 = 21 dark blue marbles.
  Fred has 63-21 = 42 red and green marbles.
  Fred has 42-4 = 38 red marbles.