He stood there, mentally calculating what their worth might be.

The system is generally too complex to mentally calculate the next media to be used.

"Get set," the corporal said, mentally calculating trajectory and speed.

He glanced down at his watch, mentally calculating how long it would take Quinn to arrive.

I believe that it is the highest sum calculated mentally.

Calculating mentally, the gambling king recalled amounts that he had sent out to pay off those who were turning in gold for paper.

He can also mentally calculate the day of the week a person was born based on their birthday.

Cloud sat down at his plate, made observations and measurements, calculated mentally.

Ivsera tried to mentally calculate how many humans had survived the war.

He was known to win card games by mentally calculating the odds.