2 + 2(2 + 2) x 2 = ?

im invisible · 09-10-2012 5:37pm #1

seen this on facebook, and the answers are mostly even numbers, anywhere from 8 to 36,
i think its meant to be set up to confuse, but it's not even set up right for that...

sometimes you'd wonder

beanie10 · 09-10-2012 5:39pm

32

CelticSpice · 09-10-2012 5:39pm

32, nach ea?

Scioch · 09-10-2012 5:41pm

Its 18 right ?

XxMCRxBabyxX · 09-10-2012 5:41pm

I thought it was 18...

PseudoFamous · 09-10-2012 5:42pm

18

2 + 2(2 + 2) * 2

2 + 2(4) * 2
2 + 8 * 2
2 + 16
18

Neeson · 09-10-2012 5:42pm

2 + 2(2 + 2) x 2 = ?

2 + 2(2 + 2) x 2 = ?
2 + 2(4) x 2 = ?

2 + 8 x 2 = ?

2+16

18

CelticSpice · 09-10-2012 5:44pm

2 + 2 x 4 x 2, nach ea?

TheBody · 09-10-2012 5:44pm

These threads pop up here every now and then. There is no mystery here. You just need to remember/learn the rules regarding the order in which you should do calculations.

2+2(2+2)x2=2+2(4)x2

=2+16

=18

NinjaTruncs · 09-10-2012 5:46pm

im invisible wrote: »

seen this on facebook, and the answers are mostly even numbers, anywhere from 8 to 36,
i think its meant to be set up to confuse, but it's not even set up right for that...

sometimes you'd wonder

Only mostly!! I'd love to know how someone would get a odd number out of that equation.

XxMCRxBabyxX · 09-10-2012 5:46pm

CelticSpice wrote: »

2 + 2 x 4 x 2, nach ea?

BOMDAS

So brackets first: (2+2)
Then the multiplication: 2(4) and then 8x2
and then the addition: 2+16

That's how I took it anyway

Neeson · 09-10-2012 5:49pm

BEMDAS.

Exponents

konman · 09-10-2012 5:49pm

i get 20

Peregrine · 09-10-2012 5:52pm

konman wrote: »

i get 20

Did you multiply the 2 into the two 2s inside the bracket like algebra?

TheBody · 09-10-2012 5:55pm

This is the most activity I've seen in the Mathematics forum in months!!

TheBody · 09-10-2012 5:56pm

Nimrod 7 wrote: »

Did you multiply the 2 into the two 2s inside the bracket like algebra?

That would still give 18 if you did it correctly.

CelticSpice · 09-10-2012 5:56pm

TheBody wrote: »

This is the most activity I've seen in the Mathematics forum in months!!

Is an-mhaith an rud é. Haha

TheBody · 09-10-2012 5:59pm

CelticSpice wrote: »

Is an-mhaith an rud é. Haha

Cinnte!!

XxMCRxBabyxX · 09-10-2012 5:59pm

Neeson wrote: »

BEMDAS.

Exponents

Are you talking to me? Aren't the two the same? Just using a different word (meaning the same thing!)?

Peregrine · 09-10-2012 6:22pm

TheBody wrote: »

That would still give 18 if you did it correctly.

Oh yeah never mind, must've added the 2 to 2(4) then multiplied the sum 10 by 2 rather than (2)(4)(2) and add 2 at the end

Snotzenfartz · 09-10-2012 9:12pm

x = (?-2)/16

Right?

Delphi91 · 09-10-2012 9:19pm

OK, on a similar vein, I came across this a month or more back on Linkedin. I'm quoting it verbatim, and I didn't make it up!

"the answer to (2/3 divide 5/6)+ 5 divide (5/4)- 1(1/3)*6 is??????? "

Stark · 09-10-2012 9:20pm

All that devoting time to religion instead of maths in primary school seems to be paying off...

Neeson · 09-10-2012 11:10pm

XxMCRxBabyxX wrote: »

Are you talking to me? Aren't the two the same? Just using a different word (meaning the same thing!)?

Ah yeah, but I'd imagine BEMDAS is the proper one - if you could call any of them proper.

delaad · 09-10-2012 11:18pm

Neeson wrote: »

Ah yeah, but I'd imagine BEMDAS is the proper one - if you could call any of them proper.

They're also using BIMDAS, with I for indices.

That's Project Maths for you now. Just like real life, where there's many different ways to say the same thing.

gerardduff · 10-10-2012 8:01am

XxMCRxBabyxX · 10-10-2012 2:30pm

Neeson wrote: »

Ah yeah, but I'd imagine BEMDAS is the proper one - if you could call any of them proper.

Well I was definitely taught BOMDAS...

Zulu · 10-10-2012 2:36pm

18

2 + 2(2 + 2) x 2 = ?
2 + 2(4) x 2 = ?
2 + 8 x 2 = ? or 2 + 2(8) = ? (no difference in the order of multiplication)
2 + 16 = 18

10-10-2012 2:46pm

Delphi91 wrote: »

OK, on a similar vein, I came across this a month or more back on Linkedin. I'm quoting it verbatim, and I didn't make it up!

"the answer to (2/3 divide 5/6)+ 5 divide (5/4)- 1(1/3)*6 is??????? "

(2/3 ÷ 5/6) + 5 ÷ (5/4) - 1(1/3) * 6 - Brackets first gives:
12/15 + 5 ÷ (5/4) - 1(1/3) * 6 - Division and multiplication next (reading left to right) gives:
12/15 + 4 - 2
= 2.8

Delphi91 · 10-10-2012 3:56pm

28064212 wrote: »

(2/3 ÷ 5/6) + 5 ÷ (5/4) - 1(1/3) * 6 - Brackets first gives:
12/15 + 5 ÷ (5/4) - 1(1/3) * 6 - Division and multiplication next (reading left to right) gives:
12/15 + 4 - 2
= 2.8

But what if 1(1/3) is taken as [latex]1\frac{1}{3}[/latex]?

Scioch · 10-10-2012 3:59pm

Delphi91 wrote: »

But what if 1(1/3) is taken as [latex]1\frac{1}{3}[/latex]?

Cant be though because that would be 1 + (1/3).

10-10-2012 4:15pm

Delphi91 wrote: »

But what if 1(1/3) is taken as [latex]1\frac{1}{3}[/latex]?

This

Scioch wrote: »

Cant be though because that would be 1 + (1/3).

1(1/3) = 1*(1/3) = 1/3

Neeson · 10-10-2012 4:46pm

XxMCRxBabyxX wrote: »

Well I was definitely taught BOMDAS...

So was I. Then it was Bemdas. And someone else has said they've changed it to Bimdas now. It's nothing but a way to remember how to do a sum anyway I suppose.

Snotzenfartz · 10-10-2012 4:57pm

BO SELECTA!

Delphi91 · 11-10-2012 4:15pm

Scioch wrote: »

Cant be though because that would be 1 + (1/3).

Not necessarily - given the limits of plain text (i.e. without the advantage of Latex), 1(1/3) could very easily represent [latex]1 \frac{1}{3}[/latex].

As I said, I didn't write the original problem, I copied it verbatim. I think it does show, however, the need for a consistent approach to the writing of mathematical problems to remove any ambiguity in interpretation.

11-10-2012 4:24pm

Delphi91 wrote: »

Not necessarily - given the limits of plain text (i.e. without the advantage of Latex), 1(1/3) could very easily represent [latex]1 \frac{1}{3}[/latex].

It could also represent 1 ^ 1/3 if you wanted to interpret it that way. By convention (which is all we have when we're not talking about a fully-qualified formal system), parentheses is shorthand notation for multiplication. You might as well ask "what is 2 + 2", then say "no, it's not 4, it's 1. In this particular example, + actually means division".

Scioch · 11-10-2012 4:34pm

Delphi91 wrote: »

Not necessarily - given the limits of plain text (i.e. without the advantage of Latex), 1(1/3) could very easily represent [latex]1 \frac{1}{3}[/latex].

As I said, I didn't write the original problem, I copied it verbatim. I think it does show, however, the need for a consistent approach to the writing of mathematical problems to remove any ambiguity in interpretation.

The expression is not limited by plain text. To represent [latex]1 \frac{1}{3}[/latex] in plain text is 1 + (1/3). It cant represent anything other than what it actually is. No more than 2 can represent 1.

And there is a consistent approach to writing problems which removes any ambiguity, and it dictates that 1(1/3) is 1 * (1/3). There is no ambiguity only a possible mistake on the authors part if they really did mean [latex]1 \frac{1}{3}[/latex].

Delphi91 · 11-10-2012 8:31pm

Scioch wrote: »

The expression is not limited by plain text. To represent [latex]1 \frac{1}{3}[/latex] in plain text is 1 + (1/3). It cant represent anything other than what it actually is. No more than 2 can represent 1.

And there is a consistent approach to writing problems which removes any ambiguity, and it dictates that 1(1/3) is 1 * (1/3). There is no ambiguity only a possible mistake on the authors part if they really did mean [latex]1 \frac{1}{3}[/latex].

I fully agree - when I saw it first I took 1(1/3) to mean 1 x (1/3) = 1/3.

Squ · 15-10-2012 5:10am

Completion is over, answer was 18

2 + 2(2 + 2) x 2 = ?

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