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I was creating a simple quiz. I noticed that wolframalpha converts 0.25 miles into 15800 inches while google converts it into 15840 inches. Is it a bug or did I make some miscalculation?

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  • $\begingroup$ If you use 1/4 miles instead of .25 miles you get ``15840` inches in WA. $\endgroup$
    – kglr
    Dec 7, 2014 at 22:31
  • $\begingroup$ @kguler any explanation for weird behaviour? $\endgroup$
    – S L
    Dec 7, 2014 at 22:32
  • $\begingroup$ Santosh, not sure... Using .250 miles also gives the correct result (WolframAlpha["convert .250 miles to inches", {{"Result", 1}, "ComputableData"}]). $\endgroup$
    – kglr
    Dec 7, 2014 at 22:38
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    $\begingroup$ WA knows about significant figures and google does not. Put 0.2500 into WA and you get improved precision $\endgroup$
    – bobthechemist
    Dec 7, 2014 at 22:38
  • $\begingroup$ Using precision implied by significant figures the "correct" answer is 16000. And how come .250005 -> 15840` not 15840.3 ? $\endgroup$
    – george2079
    Dec 8, 2014 at 18:33

1 Answer 1

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Using exact numbers or higher precision numbers gives the result that matches google's output:

WolframAlpha["convert 1/4 miles to inches", {{"Result", 1}, "ComputableData"}]
(* 15840 in *)

WolframAlpha["convert .250 miles to inches", {{"Result", 1}, "ComputableData"}]
(* 15840 in *)

Another example:

WolframAlpha["convert 1/5 miles to inches", {{"Result", 1}, "ComputableData"}]
(* 12672 in *)

WolframAlpha["convert " <> # <> "miles to inches", {{"Result", 1}, "ComputableData"}] & /@ 
{".2", ".20", ".200", ".2000"}
(* {12700 in, 12700 in, 12670 in, 12672 in} *)
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