1. slagman5's Avatar
    So, recently there was an update to the calculator. I usually read reviews to make sure nothing was messed up with the update. I learned from the reviews that the calculator does not show percentages right, so I decided to check it. And it's true, pressing the percent key results in some odd reactions. I guess I never noticed it before because I always typed the decimal version for percentages (ie for 55% I would just type .55). Anyone know why they can't fix such an issue? Apparently it's been that way for a while according to the reviews...

    ?Posted without the aid of AutoCorrect with my physical keyboard via CB10
    11-03-14 06:43 PM
  2. Morten's Avatar
    100-20% gives 80

    What is wrong with your experience?

    Never use the % symbol myself, but curious
    11-03-14 08:36 PM
  3. FF22's Avatar
    There was a very long thread or threads on how BB's Calculator does percentages. It does not follow the 'standard' established by quickie calculators. Math types agreed that it is doing it correctly but not what folks expect.
    southlander likes this.
    11-03-14 08:42 PM
  4. slagman5's Avatar
    100-20% gives 80

    What is wrong with your experience?

    Never use the % symbol myself, but curious
    But that's the thing, it inserts it into the equation, it doesn't do 100 - 20% = 80. The moment you press the percent key, it makes it 100 - 80... So if you want to actually USE the result, you'll have to delete the whole thing and type the number again, otherwise you'd be including the original number into the equation and it ruins the whole thing. For a nice round number like 80 that's not an issue, but if it's a long decimal then you have issues...

    ?Posted without the aid of AutoCorrect with my physical keyboard via CB10
    11-03-14 09:13 PM
  5. slagman5's Avatar
    There was a very long thread or threads on how BB's Calculator does percentages. It does not follow the 'standard' established by quickie calculators. Math types agreed that it is doing it correctly but not what folks expect.
    It makes the result not usable since it enters it into the equation. And that's the main downside about it.

    ?Posted without the aid of AutoCorrect with my physical keyboard via CB10
    11-03-14 09:14 PM
  6. oystersourced's Avatar
    But that's the thing, it inserts it into the equation, it doesn't do 100 - 20% = 80. The moment you press the percent key, it makes it 100 - 80... So if you want to actually USE the result, you'll have to delete the whole thing and type the number again, otherwise you'd be including the original number into the equation and it ruins the whole thing. For a nice round number like 80 that's not an issue, but if it's a long decimal then you have issues...

    ?Posted without the aid of AutoCorrect with my physical keyboard via CB10
    I don't really understand what the issue is, 110 - 20% = 88. The calculator correctly inserts 22 when you press the percentage button. The result can be stored in memory.

    Posted via CB10
    11-03-14 10:52 PM
  7. slagman5's Avatar
    I don't really understand what the issue is, 110 - 20% = 88. The calculator correctly inserts 22 when you press the percentage button. The result can be stored in memory.

    Posted via CB10
    It happens to work out for that exact situation, but what about multiplication? 110 x 20% = 22 but in this calculator 110 x 20% = 2420. Or what about division? 110 / 20% = 550, while in this calculator, 110 / 20% = 5

    No matter how you try to spin it just so you won't have to admit BB did something wrong, it's not the ideal way for that to be implemented...
    11-03-14 11:05 PM
  8. WWBlondieDo's Avatar
    It happens to work out for that exact situation, but what about multiplication? 110 x 20% = 22 but in this calculator 110 x 20% = 2420. Or what about division? 110 / 20% = 550, while in this calculator, 110 / 20% = 5

    No matter how you try to spin it just so you won't have to admit BB did something wrong, it's not the ideal way for that to be implemented...
    Just tested those exact equations on my Z10 calculator v10.3.1.26 and the instant I press "%" it changes the 20 to 0.2 and provides the correct answers when I press =

    What version are you on?

    Posted via CB10 on my VZW STL100-4 running 10.3.1.821/800 hybrid
    11-03-14 11:20 PM
  9. oystersourced's Avatar
    It happens to work out for that exact situation, but what about multiplication? 110 x 20% = 22 but in this calculator 110 x 20% = 2420. Or what about division? 110 / 20% = 550, while in this calculator, 110 / 20% = 5

    No matter how you try to spin it just so you won't have to admit BB did something wrong, it's not the ideal way for that to be implemented...
    110 x 20% does not equal 22 and I wouldn't be too impressed if a calculator told me otherwise. 110 x 20% = 110 x 22 = 2420, the BlackBerry calculator agrees.

    110 / 20% does not equal 550, 110 / 20% = 110 / 22 = 5, the BlackBerry calculator agrees again.

    I believe you are mistaking 110 x 0.2 with 110 x 20%. They are different.

    Posted via CB10
    J Morehouse and AnimalPak200 like this.
    11-03-14 11:28 PM
  10. cathulu15's Avatar
    The problem with all these examples is that you just show a calculation without the corresponding word problem first.

    So let's for example ask what is 20% of 110? This I would calculate as 110 x 0.2 = 22 and I wouldn't bother with the percent key at all. But If I use the percentage key I get 110 x 20% = 2420 so I get the wrong answer for this kind of word problem at least on 10.2.1.

    In 10.2.1 the calculator is answering the question what is 110 multiplied by 20% of 110. A stupid way to interpret the formula full stop.
    11-03-14 11:55 PM
  11. jafrul's Avatar
    It happens to work out for that exact situation, but what about multiplication? 110 x 20% = 22 but in this calculator 110 x 20% = 2420. Or what about division? 110 / 20% = 550, while in this calculator, 110 / 20% = 5

    No matter how you try to spin it just so you won't have to admit BB did something wrong, it's not the ideal way for that to be implemented...
    I did the same calculation you did.
    And the answer is correct as what you said.
    And when I tap %, it changes my 20% to 0.2. Which gives the correct answer as you mentioned.
    My calculator is version 10.1.3.34


    BlackBerry Calculator doesn't know %??-img_20141104_141754.png

    With due diligence from my Astro on Z30STA100-2/10.3.1.1016
    11-04-14 12:18 AM
  12. oystersourced's Avatar
    A stupid way to interpret the formula full stop.
    No, the correct way to interpret the formula.

    If you want 20% of 110 your brain thinks ok I better type in 110 x 0.2. The BlackBerry Calculator has scientific functions, it should act like a scientific calculator.



    Posted via CB10
    11-04-14 12:18 AM
  13. J Morehouse's Avatar
    110 x 20% does not equal 22 and I wouldn't be too impressed if a calculator told me otherwise. 110 x 20% = 110 x 22 = 2420, the BlackBerry calculator agrees.

    110 / 20% does not equal 550, 110 / 20% = 110 / 22 = 5, the BlackBerry calculator agrees again.

    I believe you are mistaking 110 x 0.2 with 110 x 20%. They are different.

    Posted via CB10
    Oyster is correct.

    Look at the equation using algebra, not numerical examples.

    Let a = a real number
    Let b = a percentage of a, such that b=ac, where c is the decimal representation of the percentage (a constant).

    The four fundamental operations are then:

    a + b = a + ac = a(1+c)
    a - b = a - ac = a(1-c)
    a/b = a/ac = 1/c
    a*b = a(ac) = ca^2

    The BlackBerry calculator is correct with all of these operations.

    The first two will be the most used equations when calculating tax, discounts, and fees. For example, if you are paying for a $65 meal and have 13% tax:

    a=65, c=0.13 -> b=ac=(65)(0.13)=8.45
    a + b = 65 + (65)(0.13) = 65+8.45 = 73.45

    I'm certain you will find the BlackBerry calculator gets the same answer.

    Posted with my BlackBerry Z10!
    oystersourced likes this.
    11-04-14 12:23 AM
  14. cathulu15's Avatar
    Maybe that is reverse polish notation? I think that is what you are thinking. But that is not how most people calculate, BlackBerry calculator app is not a HP scientific calculator.

    The result you expect begs the question 20% of what? I would suggest the correct formula for what you expect is 110 x (110 x 20%) for most people.

    I stand by my original comment. I am right, you are wrong

    Posted via CB10
    WWBlondieDo likes this.
    11-04-14 12:27 AM
  15. oystersourced's Avatar
    BlackBerry calculator app is not a HP scientific calculator.

    The result you expect begs the question 20% of what? I would suggest the correct formula for what you expect is 110 x (110 x 20%) for most people.

    I stand by my original comment. I am right, you are wrong

    Posted via CB10
    Remove the calculator functions and put a Smarties logo on the top and we have a deal.

    Posted via CB10
    11-04-14 12:34 AM
  16. imaginesaran's Avatar
    actually BlackBerry makes it easier for the common man

    Usually one wants to do something with the derived percentage value. Usually its either, add or subtract!

    so If you want to know what the total bill amount to a service is: Room Rent 5000 + 12.36% Tax
    would be: 5000+12.36%.
    The beauty of it is, the % value is immediately shown in the equation!
    So it would be 5000+618 = 5618

    Just needs a little getting used to. Be warned though, you may end up disliking the regular calculators after a while
    Last edited by imaginesaran; 11-04-14 at 02:46 AM.
    11-04-14 12:41 AM
  17. cathulu15's Avatar
    Deal. :^)

    Posted via CB10
    11-04-14 12:47 AM
  18. AnimalPak200's Avatar
    Maybe that is reverse polish notation? I think that is what you are thinking. But that is not how most people calculate, BlackBerry calculator app is not a HP scientific calculator.

    The result you expect begs the question 20% of what? I would suggest the correct formula for what you expect is 110 x (110 x 20%) for most people.

    Posted via CB10
    And that's exactly what you are inputting by saying 20% (because you are not otherwise defining the second operand of the percentage operation).

    In other words, to say "20 percent" and expect an answer is ludicrous, as it is an incomplete expression.

    Instead you have to say "20 percent of (a quantity)".

    The BlackBerry calculator completes the operand for you based on a very common application of the percentage: discounts and value added taxes.

    When you go into a store you see, "it's 20% off" (the original price), which corresponds to original price minus 20% of the original price (org-org*.20)

    Conversely you see an item and it says, "plus 5% sales tax", which corresponds to price plus 5% of the price (price+0.05*price)

    This is exactly quite literally what the calculator does when you press the percentage key. If you enter as you would speak it: "fifty (dollars) plus ten percent", you get 50+5=55

    Not sure how there is any confusion other than the fact that people misinterpret the term "percent" to be synonymous with fractions having 100 as their denominator.

    Posted via CB10
    southlander likes this.
    11-04-14 12:49 AM
  19. jafrul's Avatar
    ^^^ this makes sense to me..

    With due diligence from my Astro on Z30STA100-2/10.3.1.1016
    southlander likes this.
    11-04-14 12:51 AM
  20. slagman5's Avatar
    Just tested those exact equations on my Z10 calculator v10.3.1.26 and the instant I press "%" it changes the 20 to 0.2 and provides the correct answers when I press =

    What version are you on?

    Posted via CB10 on my VZW STL100-4 running 10.3.1.821/800 hybrid
    Mine is 10.3.0.45, and that was the latest update for me. Just checked again and no update to your version. So pretty much that proves it's a problem if they fixed it. So thanks for your reply. I find it funny all of the responses so far trying to make it seem like it works fine and like I'm doing something wrong. Typical "you're using it wrong" reply to real concerns. Glad they fixed it in v10.3.1.26

    ?Posted without the aid of AutoCorrect with my physical keyboard via CB10
    WWBlondieDo likes this.
    11-04-14 01:40 AM
  21. slagman5's Avatar
    110 x 20% does not equal 22 and I wouldn't be too impressed if a calculator told me otherwise. 110 x 20% = 110 x 22 = 2420, the BlackBerry calculator agrees.

    110 / 20% does not equal 550, 110 / 20% = 110 / 22 = 5, the BlackBerry calculator agrees again.

    I believe you are mistaking 110 x 0.2 with 110 x 20%. They are different.

    Posted via CB10
    LOL, well, if WWblondie is right, you better email BB and tell them they messed up the calculator in v10.3.1.26...

    ?Posted without the aid of AutoCorrect with my physical keyboard via CB10
    11-04-14 01:42 AM
  22. slagman5's Avatar
    I did the same calculation you did.
    And the answer is correct as what you said.
    And when I tap %, it changes my 20% to 0.2. Which gives the correct answer as you mentioned.
    My calculator is version 10.1.3.34


    Click image for larger version. 

Name:	IMG_20141104_141754.png 
Views:	653 
Size:	32.4 KB 
ID:	311958

    With due diligence from my Astro on Z30STA100-2/10.3.1.1016
    I'm assuming you meant 10.3.1.34? Because mine is 10.3.0.45 and it still does it the way I described.

    ?Posted without the aid of AutoCorrect with my physical keyboard via CB10
    11-04-14 01:47 AM
  23. slagman5's Avatar
    So all of you guys defending the calculator, better not update it to the latest version because apparently they fixed what wasn't broken...

    Anyway, like I've said, I never even noticed it before because I never used it. If where I live charged 6% tax and I wanted to know the total of something I'll simply multiply it by 1.06...

    ?Posted without the aid of AutoCorrect with my physical keyboard via CB10
    11-04-14 01:53 AM
  24. jpvj's Avatar
    Interesting thread.

    I just compared my Z30 running 10.3.1 to the calculator in Win 10 beta: They both works the same.

    A - p% is changed to A - (A x p / 100) as soon as you press the % sign.
    It does make sense to relate p% to A and not just use p/100. It seems like a way to enter "remove p% from A" on the calculator.

    A x p% is changed to A - p / 100 as soon as you press the % sign.
    Again p% is relative to A due to multiplication.


    I can definitively see the use for this behaviour, but I have never used/noticed it before. If I had to subtract p% from A, I'm just used to type A x (1-p%) where p% is p/100.

    My daughter is in 6th grade and have been working with percentages for a while now. In general they learn that p% = p/100 (e.g. 50% = 0.5). It's obvious a person like her would have to learn how the calculator works.

    I actually like the way it works. You have to know it but it's usefull.
    11-04-14 02:44 AM
  25. Dmitry Kisselyov's Avatar
    I find the way this calculator treats percentages very clear and helpful. Hope they won't "fix" it. I can relate to OP: when one wants to just find out What is 26 percent of 6532? it's an extra step. However in practice for me I always want to know the result of addition or subtraction of some percentage from/to a principal value ? and in this BlackBerry provides the best approach.
    11-04-14 03:29 AM
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