conversations.from: human
conversations.value: Edward had $17.80 to spend at the toy store. He bought 4 toy cars that cost $0.95 each and a race track that cost $6.00. How much money does Edward have left to buy more toys?
conversations.from: assistant
conversations.value: The cost of the toy cars is 4 × $0.95 = $3.80.
  The total cost of the toys is $3.80 + $6.00 = $9.80.
  Edward has $17.80 − $9.80 = $8.00 left.