conversations.from: human
conversations.value: A small store made 50 posters to advertise their products. Two-fifths of them are small posters while half of them are medium posters. The rest are large posters. How many large posters are there?
  Give me a solution to this problem
conversations.from: assistant
conversations.value: 50 x 2/5 = 20 posters are small.
  And 50/2 = 25 posters are medium.
  So 20 + 25 = 45 posters are not large.
  Therefore, 50 - 45 = 5 posters are large.