Number to Fractional String not using "round to even"?

[billko]

For sanity check:

https://www.calculatestuff.com/math/rounding-numbers-calculator?number=1.055&round_to_places=2&round... 

[Kevin_Price · Accepted solution]

Betcha it's the same basic problem as this recent thread.

Even though you typed "1.055", and the display format is set to only show 1.055, try expanding to 20 digits of precision...

-Kevin P

[billko]

Still yet, proper rounding ignores everything right of the significant digit.  If I say to round to two places, you should look no further than three.

[billko]

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@billko wrote:

Still yet, proper rounding ignores everything right of the significant digit.  If I say to round to two places, you should look no further than three.

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e.g., 1.05509 should round to two digits the same as 1.05500.

[billko]

That's also why I made the bottom branch of the code.  It shows how it gets rounded if the same digits get treated as a floating point value with just one decimal place and rounded using the rounding primitive.

[RavensFan · Accepted solution]

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@billko wrote:

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@billko wrote:

Still yet, proper rounding ignores everything right of the significant digit.  If I say to round to two places, you should look no further than three.

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e.g., 1.05509 should round to two digits the same as 1.05500.

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But going to 20 dig. precision, the number is 1.05499999999999994, thus round down to 1.05

[billko]

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@RavensFan wrote:

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@billko wrote:

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@billko wrote:

Still yet, proper rounding ignores everything right of the significant digit.  If I say to round to two places, you should look no further than three.

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e.g., 1.05509 should round to two digits the same as 1.05500.

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But going to 20 dig. precision, the number is 1.05499999999999994, thus round down to 1.05

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Ouch - that's awesome.  I thought it was going to be something like 1.05500000000001

[RavensFan]

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@billko wrote:

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Ouch - that's awesome.  I thought it was going to be something like 1.05500000000001

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Sometimes those tails of the number will go that way.  Sometimes they are under.