# 10.4.3 Calculator Wrong!

#### alexprice

##### macrumors 6502a
Original poster
Goto Calculator and switch to Scientific mode,

Do...

62 + 40% =

What is the result?

also

What version of 10.4 are you using?

In 10.4.3 I get 62.4

#### wordmunger

##### macrumors 603
I'm using Panther and I get 86.8. But technically 40% = .4, so your answer is "right" as well. It depends on the order of operations.

#### alexprice

##### macrumors 6502a
Original poster
wordmunger said:
I'm using Panther and I get 86.8. But technically 40% = .4, so your answer is "right" as well. It depends on the order of operations.
I dont understand?

40% of 62 = 62.4?

#### wordmunger

##### macrumors 603
alexprice said:
I dont understand?

40% of 62 = 62.4?
What your calculator is doing is this:

62 + (40%)
= 62 + 0.4
= 62.4

What my calculator is doing is this:

62 + (40% * 62)
= 62 + (0.4 * 62)
= 62 + 24.8
= 86.8

#### alexprice

##### macrumors 6502a
Original poster
wordmunger said:
What your calculator is doing is this:

62 + (40%)
= 62 + 0.4
= 62.4

What my calculator is doing is this:

62 + (40% * 62)
= 62 + (0.4 * 62)
= 62 + 24.8
= 86.8
Unfortunatly Maths wasn't a subject I did well on, thanks for the answer tho.

How should I do it?

62 * 1.4.

#### andiwm2003

##### macrumors 601
alexprice said:
I dont understand?

40% of 62 = 62.4?

mathematically 40% equals 0.4 . just check in EXCEL spreadsheets.

or 40% of 62 equals 62 times 0.4

what happened here is that in panther they followed the convention that the 40% is 40% of 62.

in tiger they followed the convention that excel is using.

both are correct.

#### SilentPanda

##### Moderator emeritus
alexprice said:
Unfortunatly Maths wasn't a subject I did well on, thanks for the answer tho.

How should I do it?
62 * 40%
+62

Probably... I'm not at my Mac. But it sounds like you need to get 40% of 62 then add the 62.

Or.... since you know 40% = .4 you could just do 62 * 1.4

#### alexprice

##### macrumors 6502a
Original poster
I think I understand, I thought it might be a bug as 10.4.2 doesn't do it.

Thanks for the response.

#### alexprice

##### macrumors 6502a
Original poster
I'm still a bit confused, I choose +40% of the last number (62), not 1.

Sorry if I'm starting to sound dumb, I'm just a little confused.

Thanks again.

#### ElectricSheep

##### macrumors 6502
alexprice said:
I'm still a bit confused, I choose +40% of the last number (62), not 1.

Sorry if I'm starting to sound dumb, I'm just a little confused.

Thanks again.
I don't see where there would be confusion. I think to implicitly compute 60 + 0.4*60 when you type 60 + 40% would create more confusion and is not a good way to build a calculator.

#### gco212

##### macrumors 6502
alexprice said:
I'm still a bit confused, I choose +40% of the last number (62), not 1.

Sorry if I'm starting to sound dumb, I'm just a little confused.

Thanks again.
You're not saying +40% of the last number. You're saying +40%. Percentages are just another way of writing decimals. You move the decimal 2 spots to the right, and you change from a decimal to a percentage. If you wanted to say +40% of the last number, you want to write 62 + (.4*62).

#### Abstract

##### macrumors Penryn
alexprice said:
I'm still a bit confused, I choose +40% of the last number (62), not 1.

Sorry if I'm starting to sound dumb, I'm just a little confused.

Thanks again.
You can't even use a calculator?

How does 62 + 40% = 62 + (40% of 62)?? In no way does typing in "40%" into your calculator imply that it's 40% of 62 (ie: 62 * 0.40).

Your way is confusing, and wrong. 62 *1.4 is what people do.

#### MarkCollette

##### macrumors 68000
If you type:

60 + 40%​

that makes no sense from a mathematical perspective. 40% of what?

Ok, so you expect it to be smart and know that it's:

60 + 40% of whatever came before​

So then, what should this do?

25 + 60 + 40%​

Should it be:

(25 + 60) + 40% of whatever came before ==> 119​

Or be:

25 + (60 + 40% of whatever came before) ==> 109​

For reference, what I would do, mathematically, is:

60 * 140%​

#### mwpeters8182

##### macrumors 6502
How many "the OS X calculator is wrong!!!" threads are there going to be. It works fine, I've never had an issue with it.

#### bluebomberman

##### macrumors 6502a
You know you're bad at math when you don't know enough math to use the calculator properly...

#### ohcrap

##### macrumors 6502a
This calculator "problem" has already been mentioned a few times, and it's not something anyone who knows anything about math should have a problem with.

It's not that difficult.

##### macrumors 68040
mwpeters8182 said:
How many "the OS X calculator is wrong!!!" threads are there going to be. It works fine, I've never had an issue with it.
was just about to bring this up...

good grief... if apple can write an ENTIRE OPERATING SYSTEM, then i have faith that their calculator works... save for human error

#### alexprice

##### macrumors 6502a
Original poster
I fully admit that maths isn't a subject I'm good with, the reason I thought it was wrong was because it didn't do it with 10.4.2.

Thanks for the replys, I do understand now.

The whole point in me using the calculator was that I wasn't very good with maths.

Alex

#### alexprice

##### macrumors 6502a
Original poster
Stridder44 said:

LOL!!!!

I feel like the bunny.

#### BrandonSi

##### macrumors regular
alexprice said:
LOL!!!!

I feel like the bunny.
I want the pancake.

#### jeremy.king

##### macrumors 603
The OP has a point so don't bash the guy for NOT doing anything wrong. Usually, on a REAL calculator, when you hit a number followed by the % key, it will take that percentage of whatever the result was on the display before entering in the percentage number. The point is that the Apple calculator in Tiger isn't behaving like a real calculator. Even the windows calculator will give the correct result.

If you don't believe me, try it on a good ol solar powered beauty...

62 + 40 % = 86.8

With that said, alexprice - please brush up on your math - knowing the way percentage's translate to decimals is a good skill...It will prevent you from being taken advantage of when you go to finance something or calculating a discount or a tip...

#### jeremy.king

##### macrumors 603
alexprice said:
The whole point in me using the calculator was that I wasn't very good with maths.
And the whole reason most people aren't good with Math is the calculator...

I digress...I love the look I get when I give more money than I need to a cashier so I wont get more bills and coins back...For example. If I buy something and the total is 5.78 and I give the cashier 11.03, they always look at me as to why I am giving the extra 1.03. My response is always "just trust me."

#### simie

##### macrumors 6502a
Quote:
Originally Posted by alexprice
I dont understand?

40% of 62 = 62.4?

mathematically 40% equals 0.4 . just check in EXCEL spreadsheets.

or 40% of 62 equals 62 times 0.4

what happened here is that in panther they followed the convention that the 40% is 40% of 62.

in tiger they followed the convention that excel is using.

both are correct.

10.4.3 calculator does in fact work like Excel.

Try using this formula to find 40% of 62

62*40/100 =24.8

or

62*0.4=24.8