conversations.from: human
conversations.value: Find the answer to the math problem: Mary wants to bake 10 apple pies for a charity event. Each pie needs 8 apples and she already harvested 50 apples from the trees in her garden. How many more apples does she need to buy to make all 10 pies?
conversations.from: assistant
conversations.value: She needs 10*8=80 apples to make the pies
  So she has to buy 80-50=30 more apples