Marks is having some trouble with the computations.
"The Electronic Mind Reader"
John Blaine
This third point, roughly speaking, was the open mouth of a gayly dressed young coloured man whose attention, as he strolled, had been thus violently distracted from some mental computations he was making in numbers, including, particularly, those symbols at ecstasy or woe, as the case might be, seven and eleven.
"Penrod and Sam"
Booth Tarkington
These remarkable computations were undertaken quite independently by two astronomers-one in England and one in France.
"The Story of the Heavens"
Robert Stawell Ball