6÷2(1+2)=?

Havermeyer · 28-04-2011 9:44pm

Chemistry Ftw wrote: »

The answer is 1

Nein.

As said above, both are technically correct. I came up with 9. Other people I know came up with 1.

Chemistry Ftw · 28-04-2011 9:56pm

nummnutts wrote: »

Nein.

As said above, both are technically correct. I came up with 9. Other people I know came up with 1.

Whoever says 9 is WRONG. You always work out whatever is in the brackets first and you get 1. If you use a calculator it will also tell you 1. Therefore 1 is the correct answer.

*close thread*

28-04-2011 9:57pm

Chemistry Ftw wrote: »

Whoever says 9 is WRONG. You always work out whatever is in the brackets first and you get 1. If you use a calculator it will also tell you 1. Therefore 1 is the correct answer.

*close thread*

No it won't tell you 1

Eliot Rosewater · 28-04-2011 9:58pm

What we should really do is take the answer to be a random variable, and then trawl this thread for sample values, and then use those sample values to determine the probability that it is one or the other, and finally get the random variable's expected value.

28064212 wrote: »

I don't think any of those are exactly huge leaps of logic, or entirely new concepts to maths

They're obviously not new concepts to mathematics, but they are huge leaps of logic. I could equally make the assumptions that:

Multiplication and division do not have equal precedence
Multiplication and division are right-associative

I don't see any reason to accept yours over mine?

Chemistry Ftw · 28-04-2011 9:58pm

bluewolf wrote: »

No it won't tell you 1

Then your obviously not using brackets, like everyone else.

28-04-2011 10:00pm

Chemistry Ftw wrote: »

Then your obviously not using brackets, like everyone else.

My am using brackets, but there is only one set.

Screaminmidget · 28-04-2011 10:01pm

Eliot Rosewater wrote: »

What we should really do is take the answer to be a random variable, and then trawl this thread for sample values, and then use those sample values to determine the probability that it is one or the other, and finally get the random variable's expected value.

They're obviously not new concepts to mathematics, but they are huge leaps of logic. I could equally make the assumptions that:
Multiplication and division do not have equal precedence

Multiplication and division are right-associative

I don't see any reason to accept yours over mine?

Brackets have precedence over everything..

Chemistry Ftw · 28-04-2011 10:02pm

Screaminmidget wrote: »

Brackets have precedence over everything..

What he said.

PenguinMan · 28-04-2011 10:04pm

Pretty sure this is a mind trick of some sort set out to confuse us. I initially thought 1, too, but in fact I think it's 9.

6÷2(1+2)

is actually

Uploaded with ImageShack.us

It's only when you write it down that you see it becomes 6 over 2, which is 3, times 3 = 9. I think :pac:

eilo1 · 28-04-2011 10:04pm

I put it into excell and it corrected me into putting the formula as 6/2*(1+2) which equals 9

Yahew · 28-04-2011 10:08pm

Chemistry Ftw wrote: »

Whoever says 9 is WRONG. You always work out whatever is in the brackets first and you get 1. If you use a calculator it will also tell you 1. Therefore 1 is the correct answer.

*close thread*

Heres a calculator:

www.google.com.

type the equation into google. And search.

( Not that they are right, it just demolishes the calculator argument).

If you read the thread the consensus is that the answer is ambiguous.

Chemistry Ftw · 28-04-2011 10:14pm

Yahew wrote: »

Heres a calculator:

www.google.com.

type the equation into google. And search.

( Not that they are right, it just demolishes the calculator argument).

If you read the thread the consensus is that the answer is ambiguous.

Maths wasn't designed to give ambiguous answers. If you had paid attention in 5th class maths you would have learned that the brackets are always worked out first. 1 is the answer.

28-04-2011 10:16pm

Chemistry Ftw wrote: »

Maths wasn't designed to give ambiguous answers. If you had paid attention in 5th class maths you would have learned that the brackets are always worked out first. 1 is the answer.

This has nothing to do with the brackets being worked out first. We're all assuming they are worked out first. The problem is after that.

William Powell · 28-04-2011 10:17pm

My answer is still 1 no matter what way I look at it, thats because I associate the 2(1+2) as a unit and work on that before I do anything else just in the same way I'd treat √(1+2) as the √3 and (1+2)² as 3². The reason there is no x or * as in 2x(1+2) is becuase its assumed the numeral outside the braket is multiplied by whats in the bracket, so doing the division first would be incorrect.

But I don't really expect to convince anyone who thinks the answer is 9.

PenguinMan · 28-04-2011 10:18pm

Chemistry Ftw wrote: »

Maths wasn't designed to give ambiguous answers. If you had paid attention in 5th class maths you would have learned that the brackets are always worked out first. 1 is the answer.

Brackets worked out first leaves us with

6/2 x 3.
6/2 = 3.
3 x 3 = 9.

Chemistry Ftw · 28-04-2011 10:18pm

bluewolf wrote: »

This has nothing to do with the brackets being worked out first. We're all assuming they are worked out first. The problem is after that.

Working out the brackets in this equation includes multiplying what is outside it.

brian plank · 28-04-2011 10:19pm

Chemistry Ftw wrote: »

Maths wasn't designed to give ambiguous answers. If you had paid attention in 5th class maths you would have learned that the brackets are always worked out first. 1 is the answer.

btw the answer is 9. 3(3)=9

Havermeyer · 28-04-2011 10:22pm

Chemistry Ftw wrote: »

Whoever says 9 is WRONG. You always work out whatever is in the brackets first and you get 1. If you use a calculator it will also tell you 1. Therefore 1 is the correct answer.

*close thread*

I, and many others, don't believe that to be so.

Yahew · 28-04-2011 10:24pm

Chemistry Ftw wrote: »

Maths wasn't designed to give ambiguous answers. If you had paid attention in 5th class maths you would have learned that the brackets are always worked out first. 1 is the answer.

So your first argument was that your calculator was correct, and now that you are shown a calculator with a different answer we are back to 5th class maths.

I think we've all moved on from 5th class maths in this forum.

aas · 28-04-2011 10:27pm

Eliot Rosewater wrote: »

What we should really do is take the answer to be a random variable, and then trawl this thread for sample values, and then use those sample values to determine the probability that it is one or the other, and finally get the random variable's expected value.

They're obviously not new concepts to mathematics, but they are huge leaps of logic. I could equally make the assumptions that:
Multiplication and division do not have equal precedence

Multiplication and division are right-associative

I don't see any reason to accept yours over mine?

But surely we're agreeing to work within the framework of mathematics that's commonly used around the world, in which multiplication and division have equal precedence and we perform operations from the left? No one is arguing that you can't construct a notation for arithmetic where your two rules hold, but the point is that there is an existing convention that removes any ambiguity in the expression.

Chemistry Ftw · 28-04-2011 10:27pm

Yahew wrote: »

So your first argument was that your calculator was correct, and now that you are shown a calculator with a different answer we are back to 5th class maths.

I think we've all moved on from 5th class maths in this forum.

Nope, my calculator gave me 1 as the answer so it seems that different calculators give different answers or people just arn't including the brackets.

nothing · 28-04-2011 10:33pm

The reason for getting different answers on different calculators/programs is that they have different ways of dealing with the "implied multiplication" which some programs are made to take as a precedent over other multiplication, which is where the ambiguity comes in (i.e. the multiplication between the 2 and the bracketed part being higher than regular multiplication). Of course, this equation is not in standardized non-ambiguous notation.