Since Katie entered the number 15 and it displayed 9 the machine in this case is doing whatever number you put in -6 so it displayed 9 again when 23 is entered 23-6 = 17 and that is what displayed and again for 100 and 94 so the machine is taking 6 off each time.
A, The machine is taking 6 off each time.
if you enter 77 and 6 was taken off it would be 71 so 71
B, 71
