conversations.from: human
conversations.value: Archie needs to lay sod in his backyard that measures 20 yards by 13 yards. He has a shed on it that measures 3 yards by 5 yards. How many square yards of sod will Archie need for his backyard?
  Work out the solution step by step.
conversations.from: assistant
conversations.value: 20 * 13 = 260 square yards
  3 * 5 = 15 square yards
  260 - 15 = 245 square yards
  Archie needs 245 square yards of sod.