conversations.from: human
conversations.value: Blanch has 15 slices of pizza in the fridge. During breakfast, she eats 4 slices. At lunch, Blanch eats 2 slices, then takes two slices as a snack. Finally, she consumes 5 slices for dinner. How many slices of pizza are left?
  Give me a clear explanation.
conversations.from: assistant
conversations.value: During breakfast, Blanch has 15 - 4 = 11 slices left.
  At lunch, she still has 11 - 2 = 9 slices left.
  After the snack, there are still 9 - 2 = 7 slices left.
  Finally after dinner, Blanch has 7 - 5 = 2 slices left.