He did some fast calculations, couldn't quite make them fit.

Montgomery did some fast calculations in his head.

Keen did some fast calculation and gave the throttle another notch.

After expanded memory the second requirement for spreadsheeting is fast calculations.

It is generally assumed that all spreadsheets will benefit from fast calculation but this isn't necessarily so.

Tombstone was doing some fast calculations in his head.

Vassilivich spotted one of the members and made a fast calculation.

George did some fast calculations and was surprised himself at the answer.

I did a fast calculation and stifled a sigh of relief.

But the self-preserving side of his mind was making very, very fast calculations.