conversations.from: human
conversations.value: Paul has 52 marbles. His friend gave him 28 marbles. Then, he lost 1/4 of his marbles. How many marbles does Paul have left?
conversations.from: assistant
conversations.value: Paul has a total of 52 + 28 = 80 marbles.
  He lost 1/4 x 80 = 20 marbles.
  Therefore, he has 80 - 20 = 60 marbles left.