The calculator app that comes with the Android OS apparently has an error. I've confirmed this error with two other Moto Droids and one HTC Android phone. In the calculator app enter: 3322.72 - 3321.92 then = and the answer is .799999 The correct answer is .80 This may seem like a minor point (.000001 error) but the answer is still wrong! Basic arithmetic operations should be a no brainer... A Verizon service rep confirmed this error on the Droid and Eris phones he had in their call center. I wonder if 2.1 will fix this? Does anyone else get this result?

That is hilarious...something is going on with the computational method used by the calculator...I would not worry about it...unless you are in 1st grade and cheating on your arithmetic test

cue the Beach Boys" "Round round round round, I cannot round..." It isn't the Droid, it's the Droid stock gonkulator. RealCalc gives a nice clean 0.8. -Les

Yep, definately a bug in the built in calc app, RealCalc (free on the marketplace) works fine though.

I don't know if your joking or your serious....TI-89 tends to do this type of round as well...I don't know why you would need to be that accurate..

I think he tried every numeric combination he could think of until he found one that didn't work. How long did that take?

mathematically, .79999 repeating =.8, if the 9 repeats forever. to see this, write .79 repeating equals x. 10x =7.9 repeating. 10x-x =7.2 = 9 x x=.8 there are other proofs. it's well established perhaps the droid just appreciates the subtlety of math

1 + 1 = 3, for large values of 1. Pretty funny that the 3 people whose job it was to program a calculator in android missed this, albeit small, error.

your proof is wrong... by what you set x to be, 10x-x=7.19999... assuming it's 7.2 is assuming what you're trying to prove the correct proof would be to take the limit of its p-adic expansion.

Oh no! another product of poor math education. Or perhaps you're using the Droid calculator? 7.999999999999999... - .799999999999999... =7.2 No ambiguities bub. Consider .9999999999...=x 10x=9.99999999... x=.99999999... 9x=9 x=1

No, a product of a math degree. First of all, don't appreciate the condescending attitude. Second, I would be more than happy to show you the fault in your logic.

Yeah, I thought this was pretty funny as well - it's definitely a programming problem as the error occurs across different OS versions and hardware platforms. I came across this error by chance while balancing my check book and when I came up with more than two digits after the decimal point I knew something wasn't right... Because I'm not calculating the trajectory of a rocket launch to the moon I'm not going to worry about such a small error. Even so, I'll probably get Realcalc...

I double dog dare you to prove me wrong. But by PM, so this doesn't clog the thread. though you should come back here to admit it when you realize you're wrong.

Not quite a calculator error but a throwback from floating point arithmetic. This is particularly common with computations in programming, e.g., you do not test for equality to zero but rather test for proximity to machine-epsilon: abs(x)<eps. Also, the comment above about .799999... = .8 is correct.

I tested this with a piece of paper and a R.S.V.P fine point pen and I get 0000.80 When I can go to the store tomorrow and buy a pencil I'll run the test again and see what my result is.

I remember from my advanced math education (in middle school) that .799999999...=.8, although I've never heard of epsilon. But I think everyone can agree that writing it as such is bad form, and this is clearly a glitch that should be fixed. Perhaps they should hire someone smart like ubergray to fix it. It confused me for a while when I saw that 601.1-606.3=-5.199999 To whom should one address such a bug fix request?

Les is right. The OP has an issue with significant figures. Since the less significant place in either of the numbers is 0.0x, any result should be rounded to that place. Of course, the really fault does lie in the calculator, but the operator has to know not to blindly use what the calculator gives him.