conversations.from: human
conversations.value: Mara has 12 bags with 2 marbles in each bag. Markus has 2 bags with 13 marbles in each bag. How many more marbles does Markus have?
  Can you solve this problem?
conversations.from: assistant
conversations.value: Mara has 2 x 12 = 24 marbles.
  Markus has 2 x 13 = 26 marbles.
  Markus has 26 - 24 = 2 more marbles than Mara.