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?
Yella can use the computer 8 x 7 = <<8*7=56>>56 hours for this week.
Therefore, Yella's computer usage for this week is 91 - 56 = <<91-56=35>>35 hours lesser than her computer usage last week.
#### 35