conversations.from: human
conversations.value: Solve the math problem: Isabel has some money in her piggy bank. She spent half the amount and bought a toy. She then spent half of the remaining money and bought her brother a book. If she has $51 left, how much money, in dollars, did she have at first?
conversations.from: assistant
conversations.value: After buying the toy, Isabel has 51*2=102 dollars left.
  Isabel had 102*2=204 dollars at first.