Mark Lloyd used his keyboard to write :
On 08/11/2016 07:33 PM, FromTheRafters wrote:

[snip]

Two and a 'half' digits would be good enough for displaying speeds up to
199 MPH. It cuts down on the circuitry needed in the display.

I used to have digital thermometer that had 2.5 digits, which was enough
since the thermometer couldn't handle temperatures above 140 degrees.

I would think of it as a two and a half digit display with the 'half'
being left to the reader. It could well be that a log could be kept
which logged speeds well above 100 MPH rather than a rolling over,
leaving only the display limited to two digits.

100+ could be indicated by the display flashing. Flashing "00" if anyone
managed to drive 200.

True enough. My point was that the counter wouldn't have to roll over
just because of the limits of the display.

You can display Pi on a calculator and only get so many decimal places,
yet you can then subtract 3.14159 from it and retrieve six more decimal
places in many cases. The limits of the display does not necessarily
limit the underlying calculation (or, in this case, the count).

Only by looking at the circuit or code used could I determine if the
thing actually counts modulo 100 (0 through 99 and 'rolling over'
dropping anything over 100) or just not displaying the most significant
digit.