EBay learns to add up



  • 82.01 + 62 = ?

    Over the last few days I've had values anywhere between £143 and £146. It seems to cache a particular value for a while. Occasionally it'll hit the correct value. (Red rectangles are added for emphasis.)



  • Reminds me a time when my bank changed whole software (when we switched to EUR). The numbers were all over the place. I had anywhere between -100.000€ to +250.000 euros on account. to bad that I didn't took screenshot then.



  • @DarkAngl said:

    Reminds me a time when my bank changed whole software (when we switched to EUR). The numbers were all over the place. I had anywhere between -100.000€ to +250.000 euros on account. to bad that I didn't took screenshot then.
    Not to mention that Euros aren't measured in the thousanths, just to the cents.  



  • @belgariontheking said:

    Not to mention that Euros aren't measured in the thousanths, just to the cents.
     

    There go the plans for the French remake of [i]Superman III[/i] 



  • uh... sorry, here we use "," for decimal separator and "." for thousands separator. So that's -100k€ to +250k€ :)



  • @DarkAngl said:

    uh... sorry, here we use "," for decimal separator and "." for thousands separator. So that's -100k€ to +250k€ :)

     

    Danm Europeans...looks at passport...oh wait.  Damn Europeans who use bizare numeric conventions! 

     

    Although really, it does confuse me briefly everytime I see numbers written that way.  I'm getting old, it's easy to confuse me nowdays. 



  • @DarkAngl said:

    uh... sorry, here we use "," for decimal separator and "." for thousands separator. So that's -100k€ to +250k€ :)

    Ahh, I should have realized that.  TRWTF is me. 

    Just goes to show how much we need a standard worldwide.



  • @belgariontheking said:

    Just goes to show how much we need a standard worldwide.

     

     

    I nominate , for thousands seperator and . for decimal seperator. Yup, thats the American in me being ethnocentric.

     

    (while were at it lets get rid of this metric system thing that makes WAY too much sense for us americans to ever use. units of 10? WITCHES!!!!) 



  • @DeLos said:

    I nominate ` for thousands seperator and . for decimal seperator. Yup, thats the American in me being ethnocentric.
    Fixed that to something more sane and legible.



  • @Lingerance said:

    @DeLos said:
    I nominate ~ for thousands seperator and BSTORER_ROCKS for decimal seperator. Yup, thats the American in me being ethnocentric.
    Fixed that to something more sane and legible.
     

    Fixed that to something 150% more awesome.



  • @DeLos said:

    I nominate , for thousands seperator and . for decimal seperator. Yup, thats the American in me being ethnocentric.


    (while were at it lets get rid of this metric system thing that makes WAY too much sense for us americans to ever use. units of 10? WITCHES!!!!) 

     

     

    FWIW, the UK uses , for thousands and . for decimal as well.  It's just the rest of Europe that seems to be Bizaroland :)  We also still a fair amount of imperial lying around the place...'course ours are different to yours, but you can't have everything.


    I do like Swedish dates though, they use yyyy-mm-dd, ie the ISO format. 



  • @hikari said:

    FWIW, the UK uses , for thousands and . for decimal as well.  It's just the rest of Europe that seems to be Bizaroland :)  We also still a fair amount of imperial lying around the place...'course ours are different to yours, but you can't have everything.

     



  • @morbiuswilters said:

    England: the 51st state

     

    You, sir, owe me a screen cleaning.



  • @morbiuswilters said:

     



  • @bstorer said:

    @morbiuswilters said:

     

     



  • @DeLos said:

    (while were at it lets get rid of this metric system thing that makes WAY too much sense for us americans to ever use. units of 10? WITCHES!!!!) 
     

    The metric system is way overrated.  I guess it makes the math easier if you have to do it with pen and paper, but who really does that anymore?  The one that cracks me up the most is temperature.  You end up with a scale that compresses the most interesting temperatures (i.e., the weather) into a less useful scale than Fahrenheit.  Note that the Fahrenheit scale was developed where 0 and 100 were set to encompass most of the temperatures encountered in Europe.  Why be so water-centric?

    I think a similar argument applies to other measurements, especially meters.  A unit like feet is much nicer for things like measuring people's heights.  Such as:

    5ft ~ 1.542

    6ft ~ 1.8288 

    Of course, some of this is surely due to my familiarity, but I think there's definitely something to using a system that came into being because it was useful for people to deal with, rather than convenient for doing calculations. 



  • @bstorer said:

    @morbiuswilters said:

     





  • @boomzilla said:

    Of course, some of this is surely due to my familiarity, but I think there's definitely something to using a system that came into being because it was useful for people to deal with, rather than convenient for doing calculations.

    I was actually going to make a similar point, but didn't want to start a Metric vs. Imperial flamewar.  Metric is seen as easy because the magnitudes between different scales are multiples of 10, but how often do you really need that?

    Ignorant American:  "Hmm, it's another 300 miles to Chicago."

    Arrogant European:  "How many inches, huh?  Huh?  Metric is obviously superior because once I've figure out 300 miles is 482 in km, I can tell you that we are 482.000 meters, 48.200.000 centimeters and 482.000.000 millimeters from Chicago!"

    Ignorant American:  "Oww, math!  Let's stop and get a Budweiser so I can get rid of this headache!"

     

    Seriously, the only hard part of converting measurements is going between Metric and Imperial.  Seeing as America invented numbers and gave you all freedom, the rest of the world just needs to man up and adopt our system. 



  • @morbiuswilters said:

    I was actually going to make a similar point, but didn't want to start a Metric vs. Imperial flamewar.  Metric is seen as easy because the magnitudes between different scales are multiples of 10, but how often do you really need that?

    All the time, actually.  Just the other day, I was in the store, and 2 liter bottles of soda were on sale.  But, how did the price compare to 12 packs of 12 ounce cans?  If only cans were, say, 250 ml each, it would have been a trivial calculation.  The purely imperial equivalent would involve trying to figure out how many ounces are in 2 quarts (64?  Okay, now the 12 pack has 144 ounces...)

    Let's not forget that 1 cubic cm of water = 1 ml = 1 gram, and 1 calorie = the engery required to increase the temperature of 1 gram of water 1 degree celcius.  With knowledge of those two simple facts, you have the basis for 5 different types of measurement.  All the metric units are based on easily reproducable constants.

     

    ...well, they were in the early 19th century, at least.  Apparently the definitions are now more exact, but less easily remembered.



  • @merreborn said:

    All the time, actually.  Just the other day, I was in the store, and 2 liter bottles of soda were on sale.  But, how did the price compare to 12 packs of 12 ounce cans?  If only cans were, say, 250 ml each, it would have been a trivial calculation.  The purely imperial equivalent would involve trying to figure out how many ounces are in 2 quarts (64?  Okay, now the 12 pack has 144 ounces...)

    You completely got that wrong.  Like I said, the problem is converting metric to Imperial or vice-versa.  If soda was sold in quarts you wouldn't have to do it.

     

    @merreborn said:

    Let's not forget that 1 cubic cm of water = 1 ml = 1 gram, and 1 calorie = the engery required to increase the temperature of 1 gram of water 1 degree celcius.  With knowledge of those two simple facts, you have the basis for 5 different types of measurement.  All the metric units are based on easily reproducable constants.

    Nobody uses the calorie anymore. 



  • @morbiuswilters said:

    Nobody uses the calorie anymore. 
    Cuz we're all on British Thermal Units?



  • @belgariontheking said:

    @morbiuswilters said:

    Nobody uses the calorie anymore. 
    Cuz we're all on British Thermal Units?

    Joules, fools.

     

    4.184 to the calorie, speaking of fun conversion. 



  • @bstorer said:

    @Lingerance said:
    @DeLos said:
    I nominate CONSTANTS::NUMERIC::THOUSAND_SEPARATOR for thousands seperator and CONSTANTS::NUMERIC::DECIMAL_SEPARATOR for decimal seperator. Yup, thats the American in me being ethnocentric.
    Fixed that to something more sane and legible.
    Fixed that to something 150% more awesome.
    Fixed that to something 1000% more enterprisey.



  • @mister said:

    @bstorer said:

    @Lingerance said:
    @DeLos said:
    I nominate КОНСТАНТЫ::ЧИСЛОВЫЕ::РАЗДЕЛИТЕЛЬ_ТЫСЯЧ for thousands separator and КОНСТАНТЫ::ЧИСЛОВЫЕ::ДЕСЯТИЧНЫЙ_РАЗДЕЛИТЕЛЬ for decimal separator. Yup, that's the русский in me being ethnocentric.
    Fixed that to something more sane and legible.
    Fixed that to something 150% more awesome.
    Fixed that to something 1000% more enterprisey.

    Fixed that to something наполовину l10ned.



  • @merreborn said:

    @morbiuswilters said:

    I was actually going to make a similar point, but didn't want to start a Metric vs. Imperial flamewar.  Metric is seen as easy because the magnitudes between different scales are multiples of 10, but how often do you really need that?

    All the time, actually.  Just the other day, I was in the store, and 2 liter bottles of soda were on sale.  But, how did the price compare to 12 packs of 12 ounce cans?  If only cans were, say, 250 ml each, it would have been a trivial calculation.  The purely imperial equivalent would involve trying to figure out how many ounces are in 2 quarts (64?  Okay, now the 12 pack has 144 ounces...)

     

    Or we could measure the bottles in quarts and know immediately that a case of soda is 144 ounces and equal to 4.5 (32 ounce) quarts.  I can divide pretty well as long as you use the same system.



  • @Spectre said:

    Fixed that to something наполовину l10ned.

    Stop it with the Greek. Even Google can't translate it most of the time!



  • @AbbydonKrafts said:

    Stop it with the Greek. Even Google can't translate it most of the time!

     

    I believe that was Russian.  Apparently it says "half".  At least that's what Google says.

     

    Of course it's entirely possible you were being erm...something.  But I'm half alseep, so I dunno.



  • @AbbydonKrafts said:

    @Spectre said:
    Fixed that to something наполовину l10ned.

    Stop it with the Greek. Even Google can't translate it most of the time!

     

    I just thought it was more dlikhten-speak.



  • @mister said:

    @bstorer said:

    @Lingerance said:
    @DeLos said:
    I nominate CONSTANTS::NUMERIC::THOUSAND_SEPARATOR for thousands seperator and CONSTANTS::NUMERIC::DECIMAL_SEPARATOR for decimal seperator. Yup, thats the American in me being ethnocentric.
    Fixed that to something more sane and legible.
    Fixed that to something 150% more awesome.
    Fixed that to something 1CONSTANTS::NUMERIC::THOUSAND_SEPARATOR000% more enterprisey.



  • @boomzilla said:

    I think a similar argument applies to other measurements, especially meters.  A unit like feet is much nicer for things like measuring people's heights. 

     

    I dunno about you, but my feet are slightly different lengths to each other. Should I just take the average and use that for measuring? 

    Personally, I prefer to use nano-light-seconds for measuring height. It works out to almost exactly 30cm (actually 29.979cm, but that's still a closer approximation to 30cm than 12 inches (30.48cm)).



  • Personally I prefer nanoparsecs (.308568025m) or attoparsecs, if furlongs are not an appropriate unit of length.<font size="+1"> </font>

     



  • @Physics Phil said:

    Personally I prefer nanoparsecs (.308568025m) or attoparsecs, if furlongs are not an appropriate unit of length. 

    Have I ever told you guys about the time I made the Kessel Run in less than 12x1018 attoparsecs?



  • Like you say, the problem isn't the units, but that you have no idea how people who use metric actually use metric. If it's height of a person, then I'm 187. Easy and precise, and the unit is immediately understood as implied, both when pronounced as hundred-eighty-seven and one-eighty-seven.

    Furthermore, a temperature scale based on water is important because water is important! Snow falls below zero, slush falls at zero, water falls above zero. Ice forms on rivers and seas below, melt and crack above. The wind bites below zero, but flows more easily above zero. Yes, I can detect whether it's above or below by feeling the wind.

    Water boils and food is prepared around or above 100, but not easily below 100. Water is the stuff of life, so why choose an entirely arbitrary scale?

    Even furthermore, if a system is easy to do calculations with, then by definition it is easy to deal with, even in your head.

    <disclaimer>Pressures not accounted for in preceding rant</disclaimer>



  • @boomzilla said:

    Of course, some of this is surely due to my familiarity, but I think there's definitely something to using a system that came into being because it was useful for people to deal with, rather than convenient for doing calculations. 
     

    Well, scientists all over the world use SI base units, rather than the Imperial system.  As a Canadian, all of my Chemistry, Physics, etc. high school and university textbooks were in metric, even though they were published in the U.S. 

    In physics and engineering, keeping track of significant digits and rounding errors is a very important part of doing calculations.  In the base 10 counting system, obviously there will be no rounding errors when converting between different metric units by dividing or multiplying by powers of 10.  Yes, of course, many have pointed out that computers do not use decimal, and therefore the metric system is not the best system for doing computerized calculations.  I guess there is no perfect system.

    I agree that Celsius is yet another arbitrary system of measuring temperature.  Really, the Kelvin (K) system is the only one that makes sense from a scientific standpoint.  Since the Kelvin scale starts at 0, it has the property that two temperatures expressed in K can be divided by each other for the purposes of comparison.  For example, it makes perfect sense to say that 200 degrees K is twice as hot as 100 degrees K.  Since the Fahrenheit and Celsius scales do not start at 0, it makes no sense to say, for example, that 20 degrees C is "twice as hot" as 10 degrees C (although I have seen people make this mistake).



  • @CodeSimian said:

    In physics and engineering, keeping track of significant digits and rounding errors is a very important part of doing calculations.  In the base 10 counting system, obviously there will be no rounding errors when converting between different metric units by dividing or multiplying by powers of 10.  Yes, of course, many have pointed out that computers do not use decimal, and therefore the metric system is not the best system for doing computerized calculations.  I guess there is no perfect system.

     

    How is a base-10 system any more resiliant to rounding errors?  Last time I checked multiplication and division worked the same for all numbers.  You have to keep track of significant digits when you work with metric as well.  Also, if you are doing very precise computerized calculations where significant digits matter, you use fixed-point arithmetic, not floating-point.  This isn't black magic.

     

    @CodeSimian said:

    I agree that Celsius is yet another arbitrary system of measuring temperature.  Really, the Kelvin (K) system is the only one that makes sense from a scientific standpoint.  Since the Kelvin scale starts at 0, it has the property that two temperatures expressed in K can be divided by each other for the purposes of comparison.  For example, it makes perfect sense to say that 200 degrees K is twice as hot as 100 degrees K.  Since the Fahrenheit and Celsius scales do not start at 0, it makes no sense to say, for example, that 20 degrees C is "twice as hot" as 10 degrees C (although I have seen people make this mistake).

    I was waiting for someone to chime in with Kelvin.  Yes, a system where freezing is 273.15 degrees is absolutely easy for people to work with! 



  • @morbiuswilters said:

    How is a base-10 system any more resiliant to rounding errors?  Last time I checked multiplication and division worked the same for all numbers. 
     

    When you divide and multiply by 10, in base 10, you cannot obtain a result with infinitely repeating decimals digits (e.g. 1/3).  When you divide or multiply by numbers other than 10, in base 10, you sure can.  Once you obtain a result with infinitely repeating digits, I think you just might have to round off the result, since you are only allowed to carry a certain number of significant digits in your result.  I never said you don't have to keep track of sig figs in metric.  My point is that the requirement to track sig figs also interacts with the "rounding error" problem.  

    http://www.hazelwood.k12.mo.us/~grichert/sciweb/phys8.htm 

    (Search for the section on arithmetic with significant digits).

    My point is that multiplying or dividing by 10 in base 10 can never cause the answer to be rounded (due to sig fig rules). 

     e.g.  Convert 5.0 cms to metres (where 5.0 cms is a measured value)

    5.0 cms * 1 m/100 cm  = 0.050 m 

    (5.0 cms -> 2 sig figs, 0.050 m -> 2 sig figs.  Note that the 1m /100cm term does not count when determining how many sig figs to put in the answer, since it is not a measured value.  See how no information was lost there?)

    However, if I convert 5.0 inches to feet (where 5.0 inches is a measured value):

    5.0 inches * 1 foot/ 12 inches =0.416666 (where the six is recurring)

    Since the answer has to have 2 sig figs (according to sig figs rules in physics and engineering), I am compelled to round it off to:

    0.42

    Most people would agree that 0.4166666666666666 (6 is recurring) is not equal to 0.42.  Hopefully there is no mistake in my reasoning there.  Of course, the smart thing to do would be to not convert any units until you are finished doing all intermediate calculations.  With metric, this is not a problem (at least if you are using base 10 math).

    Of course, some would argue that metric is more susceptible to rounding errors, in certain situations (e.g. binary arithmetic).  This is the same reason that some calculations/numbers cannot be represented exactly in floating-point binary (e.g. multiplying/dividing by non-powers-of-2.)

    Did you read the part of my post where I said there's no perfect system?

    @morbiuswilters said:

    I was waiting for someone to chime in with Kelvin.  Yes, a system where freezing is 273.15 degrees is absolutely easy for people to work with! 

    I think I said it makes more sense from a scientific standpoint, not that it was easier to work with for regular people.  Or do you not see the value in being able to say: x is y times as big as z?  How would you like it if your bank account's "zero point" was -273.15 USD, meaning "no debits or credits"?  

     

     



  • @CodeSimian said:

    Most people would agree that 0.4166666666666666 (6 is recurring) is not equal to 0.42.  Hopefully there is no mistake in my reasoning there.  Of course, the smart thing to do would be to not convert any units until you are finished doing all intermediate calculations.  With metric, this is not a problem (at least if you are using base 10 math).

     

    Disclaimer: I don't remember if the sig figs arithmetic rules are different when you are simply converting between units, especially since this is not usually an issue at all when using SI units.  If they are different, then obviously the whole base-10 thing less of an issue. 

    I still think it is useful to be guaranteed of an exact decimal result (i.e. no recurring decimal digits) when switching between units.  Maybe it's just me. 



  • @fbjon said:

    Water boils and food is prepared around or above 100, but not easily below 100. Water is the stuff of life, so why choose an entirely arbitrary scale?

    The explanation I like is that Farenheit is centered more on human experience. I know what about 0-100 F feels like, which is about -18-37 in Celsius.



  • No, too bad you didn't withdrew at +250.000 =)

    (and ran)



  • @Lingerance said:

    @DeLos said:
    I nominate ` for thousands seperator and . for decimal seperator. Yup, thats the American in me being ethnocentric.
    Fixed that to something more sane and legible
    You know, some of us use ' as decimal separator when writing...



  • @ender said:

    You know, some of us use ' as decimal separator when writing...
    Which is why I used a tilde instead of an apostrophe. I notice most calculators use the tilde in this manner, which IMO is quite sane, but spaces work best. Using a comma is a PITA if you happen to be reading a small font (such as when reading a screen-shot from a text-book, which is a WTF in itself). Although using an apostrophe as a decimal break is odd, where exactly is this used?



  • @Lingerance said:

    Although using an apostrophe as a decimal break is odd, where exactly is this used?
    I'm from Slovenia, but it's not actually a common practice (comma is the usual decimal separator) - I picked up the habit in elementary school, and used it ever since when doing calculations on paper.



  • @Lingerance said:

    Which is why I used a tilde instead of an apostrophe.

    ~ = Tilde

    ` (what you used) = Grave accent

     



  • @CodeSimian said:

    @morbiuswilters said:

    I was waiting for someone to chime in with Kelvin.  Yes, a system where freezing is 273.15 degrees is absolutely easy for people to work with! 

    I think I said it makes more sense from a scientific standpoint, not that it was easier to work with for regular people.  Or do you not see the value in being able to say: x is y times as big as z?  How would you like it if your bank account's "zero point" was -273.15 USD, meaning "no debits or credits"?  

     

     

    As a student, I have a £1500 interest-free overdraft facility. Therefore in real day-to-day terms, when my balance is £0, I feel like I have £1500. Of course, this is the difference between "Balance" and "Available Funds". cf celsius and kelvin.



  • @Emyr said:

    when my balance is £0, I feel like I have £1500.
     

    Excellent. How fiscally responsible.



  • @Emyr said:

    As a student, I have a £1500 interest-free overdraft facility. Therefore in real day-to-day terms, when my balance is £0, I feel like I have £1500. Of course, this is the difference between "Balance" and "Available Funds". cf celsius and kelvin.

    plz send me the codez for imaginary monies! 



  • @MasterPlanSoftware said:

    @Emyr said:

    when my balance is £0, I feel like I have £1500.
     

    Excellent. How fiscally responsible.



     There is no way I could have reached this far in my degree had I attempted to stay above £0. I would have had to take on far too many shifts, and my coursework would have been left undone, or of low quality. As it is, I've managed to keep my employment to a minimum, and am on track for a first-class degree.


    So ya-boo to you too.

     

    @morbiuswilters said:

    plz send me the codez for imaginary monies! 

     Codez:

    HAI

    CAN HAZ UNICORS?

    IM IN A HSBC:

    CAN HAZ STOODUNT AKOUNT?

    VISIBLE "HAZ MONIEZ!"

    KTHXBAI

     



  • @Emyr said:

    So ya-boo to you too.
     

    And yet the degree is not going to save you from being a jackass.

    Grow up and work for a living. Habitually maintaining a negative balance is called 'being a loser'.

    Someone as smart as you seem to think you are would have worked and saved, and then gone to school with that money, working to build the account back up before reaching a zero balance.

     

    Seriously, don't try and justify the behavior. It is just stupid and irresponsible.



  • There's a completely different attitude to university education and paying for it in the UK. Whilst I agree that treating your entire interest-free overdraft as your own money is fiscally irresponsible and forms bad habits (and generally a Bad Idea), I disagree with the rest of your post.


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