conversations.from: human
conversations.value: Break down this math problem: Miss Molly surveyed her class of 30 students about their favorite color. Half of the class answered green, one-third of the girls answered pink, and the rest of the class answered yellow. If there are 18 girls in the class, how many students like yellow best?
conversations.from: assistant
conversations.value: 30/2 = 15 students answered green.
  18/3 = 6 girls answered pink.
  So, 15 + 6 = 21 students answered either green or pink.
  Therefore, 30 - 21 = 9 answered yellow.