conversations.from: human
conversations.value: Solve the math problem: Lizzie has half as many crayons as Bobbie. Bobbie has three times as many crayons as Billie. If Billie has 18 crayons, how many crayons does Lizzie have?
conversations.from: assistant
conversations.value: Bobbie has 18 * 3 = 54 crayons.
  Lizzie has 54 / 2 = 27 crayons.