conversations.from: human
conversations.value: Bert bought some unique stamps for his collection. Before the purchase, he had only half the stamps he bought. If he bought 300 stamps, how many stamps does Bert have in total after the purchase?
  Give me a solution to this problem
conversations.from: assistant
conversations.value: Before the purchase, Bert had 300 * 1/2 = 150 stamps.
  So after the purchase he has 300 + 150 = 450 stamps.