conversations.from: human
conversations.value: A 220-liter barrel has a small leak. It lost 10% of its contents before anyone noticed. How many liters are left in the barrel?
conversations.from: assistant
conversations.value: The barrel lost 220 * 10 / 100 = 22 liters before anyone noticed.
  So, 220 – 22 = 198 liters are left in the barrel.