[plt-scheme] fractions and decimals

From: Paul Schlie (schlie at attbi.com)
Date: Mon Jan 20 11:05:43 EST 2003

Your understanding of was correct, the converse isn't bad either,
maybe better:

A) zero(0) and repeat(_) terminated decimal fractions being exact,
inexact otherwise:

1    == 1     ; exact
1.   == 1.    ; inexact
1.0  == 1     ; exact
1.1  == 1.1   ; inexact
1.10 == 11/10 ; exact
1.1_ == 10/9  ; exact

vs.

B) non-zero(1-9) and repeat(_) terminated decimal fractions being exact,
inexact otherwise:

1    == 1     ; exact
1.   == 1.    ; inexact
1.0  == 1.0   ; inexact
1.1  == 11/10 ; exact
1.10 == 1.10  ; inexact
1.1_ == 10/9  ; exact

Option A does seem arguably more reasonable,

-paul-

on 1/20/03 10:11 AM, Matthew Flatt wrote:
>
> At Sun, 19 Jan 2003 21:00:23 -0500, Paul Schlie wrote:
>> Wonder if broadly adopting the convention that decimals terminated with a
>> zero (0), would be interpreted as an inexact number, otherwise considered
>> exact; would help unify the two worlds;
> 
> I may be misunderstanding the proposal, but I don't think this would
> solve the problem for the teaching levels. For example, when working
> with American dollars, students expect "0.10" to mean exactly a dime.
> 
> Matthew
> 



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