conversations.from: human
conversations.value: Yella's computer usage last week was 91 hours. If she plans to use the computer 8 hours a day for this week, how much less ​is her computer usage for this week?
conversations.from: assistant
conversations.value: Yella can use the computer 8 x 7 = 56 hours for this week.
  Therefore, Yella's computer usage for this week is 91 - 56 = 35 hours lesser than her computer usage last week.