Anyone using Google Drive spreadsheet ever caught a math error?

[Irving]

I use Google Drive spreadsheets to track things. I'll have to look up the exact name, but it is basically the Google version of Microsoft Excel. Today I noticed that when it was summing a certain column of numbers, it was off by one cent. $.01. For the life of me I cannot figure out where the error is. Well, basically when it adds a number that ends in .51 to a number that ends in .11, it comes up with .63 instead of .62. I can't figure out why. At this point it really doesn't matter, and I don't have time right this second to try a bunch of tests, but I'm wondering if anyone has ever caught a program making a math error before.

[00tec]

Just tested on mine and got the same result.

[Sawin]

Millennials.

[mattiooo]

Sounds like a rounding result. Are the numbers longer than that and being rounded to 2 decimal places? Even though they display rounded, the full number is calculated in formulas.

[Irving]

Just tested on mine and got the same result.

Really, or are you just messing with me because my post is vague?

Sounds like a rounding result. Are the numbers longer than that and being rounded to 2 decimal places? Even though they display rounded, the full number is calculated in formulas.

I thought it might be that, but I checked the same columns in different months and those numbers all came out correct. In this specific case it is all currency, so rounding shouldn't be an issue. I thought it might have something to do with the fact that the entire column is generated by taking a percentage of a number in the prior column, and that was somehow causing a rounding error, but again, I tried the same columns in other months and everything is fine. Further, the column is broken down into weeks. When I add the week totals together, everything works out. When I have time later tonight I'll see if I can post some screen shots to give a more clear picture.

[mattiooo]

I thought it might be that, but I checked the same columns in different months and those numbers all came out correct. In this specific case it is all currency, so rounding shouldn't be an issue. I thought it might have something to do with the fact that the entire column is generated by taking a percentage of a number in the prior column, and that was somehow causing a rounding error, but again, I tried the same columns in other months and everything is fine. Further, the column is broken down into weeks. When I add the week totals together, everything works out. When I have time later tonight I'll see if I can post some screen shots to give a more clear picture.

Currency by default rounds up to the nearest penny, so my guess would still be rounding - for example:

If you took 43% of $97.37, the formula is 97.37 * .43 you would get 41.8691, but in a currency column, that would display as $41.87. However under that display is still 41.8691, and that is what is used in subsequent formulas.
Without seeing actual numbers, it's hard for me to say if that is what is happening to you, but that seems what is most likely to me.

One way you can check is to change the formatting of all the currency columns or rows to numbers.

Hope that helps.

[def90]

Currency by default rounds up to the nearest penny, so my guess would still be rounding - for example:

If you took 43% of $97.37, the formula is 97.37 * .43 you would get 41.8691, but in a currency column, that would display as $41.87. However under that display is still 41.8691, and that is what is used in subsequent formulas.
Without seeing actual numbers, it's hard for me to say if that is what is happening to you, but that seems what is most likely to me.

One way you can check is to change the formatting of all the currency columns or rows to numbers.

Hope that helps.

This.. it displays the result as a rounded number but the original number remains behind the scenes to be used in any additional formulas.

[00tec]

Really. Did it once, then I went to grab a screenshot and couldn't get it to do it again.

[Irving]

Really. Did it once, then I went to grab a screenshot and couldn't get it to do it again.

I knew it! Turns out mankind is just as responsible for math errors as rising temperatures.

[RblDiver]

I knew it! Turns out mankind is just as responsible for math errors as rising temperatures.

I forget the exact values, but in the game Mass Effect 2, an AI character Legion explains that the difference between his group (the "True Geth") and a splinter group (the "Heretics") is that a calculation that his group evaluates as 0.051 is evaluated by their group as 0.052.