Significant digits in a float?

[Adam Funk]

On 2014-05-02, Dennis Lee Bieber wrote:

> On Thu, 01 May 2014 21:55:20 +0100, Adam Funk <a24061 at ducksburg.com>
> declaimed the following:
>
>>On 2014-05-01, Dennis Lee Bieber wrote:

>>> 	Math teacher was selling them in my 10th grade... Actually I already
>>> owned a Faber-Castell 57/22 "Business" ruler (which did NOT have the CF/DF
>>> scales set for *PI) and a Pickett N-1010-ES Trig rule.
>>
>>What does a "business" slide-rule do?  Depreciation?
>>
>
> 	Special markers for: dozen, gross; a scale for "non-metric measures" to
> metric equivalents -- US Bushel, UK ("brit") bushel, US gallon, UK gallon,
> short and long tons, a few Russian units, "Pud" and "R.t." which appear to
> map to cubic inch and cubic foot; markings for % (discount and mark-up)
>
> 	And a scheme for simple interest calculations (which may explain why
> the CF/DF scales are longer than the C/D scales): "Move the main cursor
> line over the principal on scale DF -- the principal must be taken only on
> scale DF -- set the rate per cent on the scale CI, under the short cursor
> line, and read the interest on the scale DF or D in line with the number of
> days on the scale CF or C." {yes, just to the left of the normal cursor is
> a short line only over the inverted C scale}

Interesting, thanks.

-- 
I used to be better at logic problems, before I just dumped
them all into TeX and let Knuth pick out the survivors.
                                               -- plorkwort