
Maths... they do still teach it in schools, right?
Last post 03082013 10:24 AM by blakeyrat. 34 replies.

03052013 9:05 AM



Charleh
 Joined on 04112010
 Posts 73

Maths... they do still teach it in schools, right?
I'm on facebook, checking how many awesome friends I have when I see this: 6  1 x 0 + 2 / 2 ANSWER IT "Challenge Accepted" I think to myself. I do mention that it depends on the order of precedence  but the correct answer taking that into account is 5. Several thousand people have answered, some of them citing the above 'rules'  but a lot of people are coming to a conclusion of 7 SEVEN....? I asked how anyone had got to 7 and some guy came out with some bullshit about the subtract sign inverting the 1 making it 6 + ((1 x 0) + (2 / 2))... how exactly the fuck does that work? Do I need to go on a bell tower climbing killing spree with a sniper rifle or are people just making this maths shit up on the fly? Tomorrow I expect to walk into a shop, spend £9.35, give the cashier £10 and get 7p change because they just decided to add some their own bullshit rules or maybe they are just counting in base 11.5... Then I realise its 7 :D
Get to da CHOPPAAAAA




mott555
 Joined on 08102009
 Omaha
 Posts 797

Re: Maths... they do still teach it in schools, right?
The minus sign doesn't matter. 6 + 0 is the same as 6  0.




pkmnfrk
 Joined on 05102010
 Posts 366

Re: Maths... they do still teach it in schools, right?
BEDMAS:
 Brackets
 Exponents
 Division, Multiplication
 Addition, Subtraction
= 6  1 x 0 + 2 / 2
= 6  (1 x 0) + (2 / 2)
= 6  (0) + (1)
= 6 + 1
= 7
Where did 5 come from?




Charleh
 Joined on 04112010
 Posts 73

Re: Maths... they do still teach it in schools, right?
Well, I ended up doing it right to left and forgetting about the minus/plus precedence  then I headdesked.
Get to da CHOPPAAAAA




dhromed
 Joined on 04132005
 Dutchland
 Posts 11,668

Re: Maths... they do still teach it in schools, right?
Charleh: or are people just making this maths shit up on the fly? Only the imaginary numbers. PADUMTISH
In complex analysis, a meromorphic function on an open subset D of the complex plane is a function that is holomorphic on all D except a set of isolated points




Master Chief
 Joined on 08292008
 Posts 618

Re: Maths... they do still teach it in schools, right?
Charleh: I'm on facebook, checking how many awesome friends I have when I see this: 6  1 x 0 + 2 / 2 ANSWER IT "Challenge Accepted" I think to myself. I do mention that it depends on the order of precedence  but the correct answer taking that into account is 5. Several thousand people have answered, some of them citing the above 'rules'  but a lot of people are coming to a conclusion of 7 SEVEN....? I asked how anyone had got to 7 and some guy came out with some bullshit about the subtract sign inverting the 1 making it 6 + ((1 x 0) + (2 / 2))... how exactly the fuck does that work? Do I need to go on a bell tower climbing killing spree with a sniper rifle or are people just making this maths shit up on the fly? Tomorrow I expect to walk into a shop, spend £9.35, give the cashier £10 and get 7p change because they just decided to add some their own bullshit rules or maybe they are just counting in base 11.5... Then I realise its 7 :D
*Complains about people not knowing maths.
*Doesn't know maths.
All the technology and software in the universe is just as useless when the end user has the IQ of a sack of hammers.  Me




CodeNinja
 Joined on 12062011
 Posts 150

Re: Maths... they do still teach it in schools, right?
Master Chief: Charleh: I'm on facebook, checking how many awesome friends I have when I see this: 6  1 x 0 + 2 / 2 ANSWER IT "Challenge Accepted" I think to myself. I do mention that it depends on the order of precedence  but the correct answer taking that into account is 5. Several thousand people have answered, some of them citing the above 'rules'  but a lot of people are coming to a conclusion of 7 SEVEN....? I asked how anyone had got to 7 and some guy came out with some bullshit about the subtract sign inverting the 1 making it 6 + ((1 x 0) + (2 / 2))... how exactly the fuck does that work? Do I need to go on a bell tower climbing killing spree with a sniper rifle or are people just making this maths shit up on the fly? Tomorrow I expect to walk into a shop, spend £9.35, give the cashier £10 and get 7p change because they just decided to add some their own bullshit rules or maybe they are just counting in base 11.5... Then I realise its 7 :D
*Complains about people not knowing maths.
*Doesn't know maths.




Quango
 Joined on 07152008
 Posts 68

Re: Maths... they do still teach it in schools, right?
BODMAS, as my maths teacher used to say..
[B]rackets (parantheses, actually, but it sounds better than PODMAS)
[O]f (aka "multiply")
[D]ivision
M]ultiplication
[A]ddition
[S]ubtraction
Put into any spreadsheet and that's the answer.
= Quango =




joe.edwards
 Joined on 08142006
 Dallas, TX
 Posts 2,384

Re: Maths... they do still teach it in schools, right?
Quango: BODMAS, as my maths teacher used to say..
[B]rackets (parantheses, actually, but it sounds better than PODMAS)
[O]f (aka "multiply")
[D]ivision
M]ultiplication
[A]ddition
[S]ubtraction
Put into any spreadsheet and that's the answer.
PEMDAS in these parts. Parentheses, exponents, multiplication/division, addition/subtraction. I swear my sixth grade teacher turned it into a song that we had to sing for a grade.
Signatures are stupid.




PJH
 Joined on 02142007
 Newcastle, UK
 Posts 3,836

Re: Maths... they do still teach it in schools, right?
Quango: BODMAS, as my maths teacher used to say..
[B]rackets (parantheses, actually, but it sounds better than PODMAS)
[O]f (aka "multiply")
[D]ivision
M]ultiplication
[A]ddition
[S]ubtraction
Put into any spreadsheet and that's the answer.
Your Maths teacher was somewhat incorrect; or you're misremembering  the O stands for Orders (exponents and roots).
"Because you watched 'The Very Hungry Caterpillar,' we recommend 'The Human Centipede.'" UED  Countryside: To kill Piers Morgan




blakeyrat
 Joined on 10292008
 Posts 10,004

Re: Maths... they do still teach it in schools, right?
Master Chief: *Complains about people not knowing maths.
*Doesn't know maths.
THAT is the joke!
< I couldn't make my shit work, so here's a Godzilla head.





cellocgw
 Joined on 06082006
 Posts 1

Re: Maths... they do still teach it in schools, right?
Fucking Maths: How do They Work?
Every time I start thinking that the posters to TDWTF or slashdot are freaking boneheads, I just go over and read a couple Facebook or Yahoo threads. Then I realize what true microcraniality is.




Ben L.
 Joined on 12212010
 HELP I'M TRAPPED IN A COMMUNITY SERVER FACTORY
 Posts 3,401

Re: Maths... they do still teach it in schools, right?
Minus is rightassociative, riiiiiiiiight?
mi'e .ben.ly. .i na selju'o mi la lojban




GoatRider
 Joined on 09282010
 Posts 23

Re: Maths... they do still teach it in schools, right?
Don't feed the trolls. It's deliberately intended to be ambiguous, so you'll comment on it. They are trolling for comments and likes. Accounts with a lot of comments and likes are valuable to advertisers.




topspin
 Joined on 03072008
 Posts 320

Re: Maths... they do still teach it in schools, right?
GoatRider: Don't feed the trolls. It's deliberately intended to be ambiguous, so you'll comment on it. They are trolling for comments and likes. Accounts with a lot of comments and likes are valuable to advertisers. What? No it's not, it's perfectly clear. This one is deliberately ambiguous: a/b(c+d) Because written as a/b*(c+d) the left to right rule gives this order of evaluation: (a/b)*(c+d). But the ommited multiplication sign creates ambiguity because that's usually only done in situations where you would have this order of evaluation: a/(b*(c+d)), the same way as writing it out as a fraction gives you implicit parentheses: a  b*(c+d)




too_many_usernames
 Joined on 12092005
 The Mitten
 Posts 551

Re: Maths... they do still teach it in schools, right?
I was just reading the Excel woes sheet  and it kind of crosses with this thread: Type this into Excel and be angry: Cell A1: =5 Cell A2: =a1^2+1 Cell A3: =+1a1^2
You can actually find the history behind this !!fun!! with a search, but it's still irritating. I don't know how many spreadsheets have given me funny results because of this "design choice."




joe.edwards
 Joined on 08142006
 Dallas, TX
 Posts 2,384

Re: Maths... they do still teach it in schools, right?
too_many_usernames: I was just reading the Excel woes sheet  and it kind of crosses with this thread: Type this into Excel and be angry: Cell A1: =5 Cell A2: =a1^2+1 Cell A3: =+1a1^2
You can actually find the history behind this !!fun!! with a search, but it's still irritating. I don't know how many spreadsheets have given me funny results because of this "design choice."
Am I missing something?
a1^2+1 = 5^2+1 = 25 + 1 = 26
+1a1^2 = +1  (5)^2 = +1  25 = 24
Which is exactly the result I get from Excel...
Signatures are stupid.




_leonardo_
 Joined on 11092012
 Posts 51

Re: Maths... they do still teach it in schools, right?
too_many_usernames: Cell A1: =5 Cell A2: =a1^2+1 Cell A3: =+1a1^2
A2 has the value of (5) raised to the second power, with one added to the result.
Do you want it to have the value of (5) raised to the third power? If so, you need parentheses!




bjolling
 Joined on 06082008
 Belgium
 Posts 751

Re: Maths... they do still teach it in schools, right?
joe.edwards: Am I missing something?
a1^2+1 = 5^2+1 = 25 + 1 = 26
+1a1^2 = +1  (5)^2 = +1  25 = 24 Which is exactly the result I get from Excel...
The question is on the precedence on the  sign in front of the A1. Either you write a1^2+1 = (5)^2+1 = 25 + 1 = 24
+1a1^2 = +1  (5)^2 = +1  25 = 24
or by using the rule that "A1" is exactly the same as "+ ( 1 * A1 ): a1^2+1 = (1 * 5)^2+1 = 25 + 1 = 26
+1a1^2 = +1 + (1 * 5)^2 = +1  25 = 26
The second one, giving 26, seems wrong. Taking the power of 2 of A1 should have precedence over applying the minus sign
It's... Monkey Piston's Frying Circle!




pkmnfrk
 Joined on 05102010
 Posts 366

Re: Maths... they do still teach it in schools, right?
I think the point is that the minus sign in A2 is being treated differently than in A3. Eg, in A2, it has higher priority than the exponent:
=(a1)^2+1
Instead of
=(a1^2)+1
Whereas in A3, the minus sign is the subtraction operator, and has a lower priority than the exponent. If you rewrite A2 like this, it matches A3:
=0a1^2+1
I guess they added logic to handle minus signs in places where subtraction doesn't make sense, like the beginning of the formula, or this:
=5 + a1




ekolis
 Joined on 01092008
 Cincinnati, OH, USA
 Posts 600

Re: Maths... they do still teach it in schools, right?
TRWTF is British English. If it's really "maths", it should be "they do still teach THEM in schools, right?"
I'm Spark Mandrill, and I'll... hey... can I... what, it BOUNCES?... 'kay, I'm splodin' now.




joe.edwards
 Joined on 08142006
 Dallas, TX
 Posts 2,384

Re: Maths... they do still teach it in schools, right?
I guess I see it that  can be a unary operator or a binary operator, and that as a unary operator it yields the additive inverse of the number and has immediate precedence, while as a binary operator it has lesser precedence. In any case, it's acting in line with my expectations. x is evaluated as (1x).
Signatures are stupid.




pjt33
 Joined on 12062005
 Posts 568

Re: Maths... they do still teach it in schools, right?
Charleh: Well, I ended up doing it right to left and forgetting about the minus/plus precedence  then I headdesked.
In that case you should get 1, not 5.
You'll probably find that the forum experience is improved by going to the "Site Options" tab of "Edit Profile" and turning off "Display User Signatures".




TGV
 Joined on 10092005
 Posts 688

Re: Maths... they do still teach it in schools, right?
pkmnfrk: BEDMAS:
 Brackets
 Exponents
 Division, Multiplication
 Addition, Subtraction
= 6  1 x 0 + 2 / 2
= 6  (1 x 0) + (2 / 2)
= 6  (0) + (1)
= 6 + 1
= 7
Where did 5 come from? Congratulations. You are the 100,000 person who didn't read the whole story. You have won an Internet!




too_many_usernames
 Joined on 12092005
 The Mitten
 Posts 551

Re: Maths... they do still teach it in schools, right?
TGV: Congratulations. You are the 100,000 person who didn't read the whole story. You have won an Internet! Is that the onehundred thousandth person, or the one hundredth to a precision of one thousandth? (Yes, this is intentional).





da Doctah
 Joined on 02202010
 Posts 1,348

Re: Maths... they do still teach it in schools, right?
ekolis: TRWTF is British English. If it's really "maths", it should be "they do still teach THEM in schools, right?"
And if it's British English, right? should be innit?




pkmnfrk
 Joined on 05102010
 Posts 366

Re: Maths... they do still teach it in schools, right?
TGV: pkmnfrk: BEDMAS:
 Brackets
 Exponents
 Division, Multiplication
 Addition, Subtraction
= 6  1 x 0 + 2 / 2
= 6  (1 x 0) + (2 / 2)
= 6  (0) + (1)
= 6 + 1
= 7
Where did 5 come from? Congratulations. You are the 100,000 person who didn't read the whole story. You have won an Internet!
I was calling into attention a bit of the story that you clearly did not read:
Charleh: but the correct answer taking that into account is 5.




RTapeLoadingError
 Joined on 09232009
 Posts 507

Re: Maths... they do still teach it in schools, right?
My guess...
pkmnfrk: I was calling into attention a bit of the story that you clearly did not read:
Charleh: but the correct answer taking that into account is 5.
= 6  1 x 0 + 2 / 2
= 6  (1 x 0) + (2 / 2)
= 6  (0 + 1)
Certified Internet Engineer (CIE)




PJH
 Joined on 02142007
 Newcastle, UK
 Posts 3,836

Re: Maths... they do still teach it in schools, right?
RTapeLoadingError: = 6  (1 x 0) + (2 / 2)
= 6  (0 + 1)
But clearly wrong, because those two aren't equivalent, since you're introducing a multiplication in the second one.
"Because you watched 'The Very Hungry Caterpillar,' we recommend 'The Human Centipede.'" UED  Countryside: To kill Piers Morgan




Cbuttius
 Joined on 01282010
 Posts 117

Re: Maths... they do still teach it in schools, right?
pkmnfrk:
BEDMAS:
 Brackets
 Exponents
 Division, Multiplication
 Addition, Subtraction
= 6  1 x 0 + 2 / 2
= 6  (1 x 0) + (2 / 2)
= 6  (0) + (1)
= 6 + 1
= 7
Where did 5 come from?
5 comes from inserting an invisible parentheses that don't belong, opening either before the 1 or the 0 and ending at the end of the statement.
Solving in reversepolish notation you get:
6 (push), 1 (push), 0 (push), (multiply), (subtract), 2 (push), 2 (push), (divide), (add)
Each operation either pushes a number onto the stack or performs a binary operation between the 2 most recent numbers on the stack.
A subtract subtracts the current value from the one before it on the stack.
An operation replaces the last 2 numbers on the stack with the value of the current one.
Stack looks like this:
(push 6) 6
(push 1) 6, 1
(push 0) 6, 1, 0
(multiply) 6, 0
(subtract) 6
(push 2 ) 6, 2
(push 2) 6, 2, 2
(divide) 6, 1
(add) 7




blakeyrat
 Joined on 10292008
 Posts 10,004

Re: Maths... they do still teach it in schools, right?
Mr CButtius! Will the test be graded on a curve? I did bad on the quiz because my dog was barking and kept me up but I need a C on the test or I won't be able to go to prom!!!
God you people are boring.
< I couldn't make my shit work, so here's a Godzilla head.




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