According to my rough calculations, we couldn't be more than two or three miles from the state road.

To predict if this method would be possible, they made use of a rough calculation.

According to John's rough calculations, the accident was miles ahead of them.

For my rough calculation this comes to about one in 250 trillion.

A rough calculation gave them about a day's warning before the visitors arrived.

Some rough calculations in his head told him it was about a thousand miles.

Now, there are some interesting features of this rough calculation.

These figures are rough calculations I made on the flight back, but they should be accurate to within two percent.

John rolled his eyes as he did a rough calculation.

These details and a few rough calculations raise an interesting possibility.