What is 1+2x3?

What is 1+2x3?

53 posts
20 July 2013
njb
Photographer
njb
My calculator says "It's a boy...!!"
Posted 22 July 2013
pmeu
Photographer
pmeu
stolenfaces
It's not mathematics - it's arithmetic
Arithmetic is a branch of mathematics. So it is mathematics.
Posted 22 July 2013
EdT
Photographer
EdT
StreetModel
Now THAT one you'll have to explain because I bet very few people have HP calculators...
It's not just interesting for 1970s HP calculators (or sinclair for that matter). If you've ever written a compiler for just about any modern computer language (or any just aboay any computer language) you would have a good grasp of Reverse Polish Notation.
Posted 28 July 2013
StreetModel
Photographer
StreetModel
I remember the days of Cobol with phrases such as

'Add A to B giving C'

RPN calculators confuse the hell out of people that are not used to them, though... 'Hey - where is the equals button?'



Posted 28 July 2013
mikethefoto
Photographer
mikethefoto
Depends on whether you are buying or selling?

Posted 29 July 2013
Ron_H
Photographer
Ron_H
Depends where you put your brackets:
(1 + 2) x 3 = 9
1 + (2 x 3) = 7

Posted 29 July 2013
StreetModel
Photographer
StreetModel
Ron_H

Depends where you put your brackets: (1 + 2) x 3 = 9 1 + (2 x 3) = 7


I agree, but the question as asked has NO brackets - so what is the answer then?
Posted 29 July 2013
Ron_H
Photographer
Ron_H
StreetModel
I agree, but the question as asked has NO brackets - so what is the answer then?
If you do it in your head the answer is obviously 9, but you cant give a definitive answer using a calculator as different calculators work it out differently. But as a mathematical equation you WOULD have brackets in one place or the other (for that very reason).
Posted 29 July 2013
mantisphoto
Photographer
mantisphoto
Ron_H

If you do it in your head the answer is obviously 9, but you cant give a definitive answer using a calculator as different calculators work it out differently. But as a mathematical equation you WOULD have brackets in one place or the other (for that very reason).


No....... if YOU do it in your head its 9... but for those who understand BIDMAS like myself, when we do it in our heads we get 7!!

There is no need for brackets in this equation UNLESS you intend it to be (1+2) x 3 or 3(1+2) as it would be easier written. Mathematic equations are best in their simplest form, and 1 + 2 x 3 = 7 whether you write is like that or 1 + (2 x 3). 

Posted 29 July 2013
stolenfaces
Photographer
stolenfaces
mantisphoto
No....... if YOU do it in your head its 9... but for those who understand BIDMAS like myself, when we do it in our heads we get 7!! There is no need for brackets in this equation UNLESS you intend it to be (1+2) x 3 or 3(1+2) as it would be easier written. Mathematic equations are best in their simplest form, and 1 + 2 x 3 = 7 whether you write is like that or 1 + (2 x 3). 
So if the person who wrote down the expression doesn't understand BIDMAS you will have the wrong answer to the actual real-world question. It takes two people to communicate - your attitude is rather similar to Britons abroad who just shout in the belief that people who don't understand English must surely be deaf.
Posted 29 July 2013
mantisphoto
Photographer
mantisphoto
If the person writing down the equation has no understanding, then they are wrong, but somebody who applied BIDMAS correctly would always be correct.

Just because 1 person is wrong, it doesnt make both wrong, and I am NOT ignorant... quite the opposite... I am the one sharing factually correct information.
Posted 29 July 2013
stolenfaces
Photographer
stolenfaces
mantisphoto
If the person writing down the equation has no understanding, then they are wrong, but somebody who applied BIDMAS correctly would always be correct. Just because 1 person is wrong, it doesnt make both wrong, and I am NOT ignorant... quite the opposite... I am the one sharing factually correct information.
It's an expression or in the context of this thread 'a calculation', not an equation. You claim to be aware that a large number of people would resolve the expression incorrectly, but still say that using brackets isn't necessary, indeed that they should be avoided. I wouldn't have thought that was particularly ignorant just pig-headed. Although, in a sense your lack of understanding of the real-world problem exactly mimics an ignorant and mechanical calculator which merely executes the arithmetic according to pre-programmed logic, with no intelligence at all.
Posted 29 July 2013
click_gotcha
Photographer
click_gotcha
pmeu

Arithmetic is a branch of mathematics. So it is mathematics.


 I have an O level in Maths.  I also have an O level in Arithmetic. 

Posted 29 July 2013
mantisphoto
Photographer
mantisphoto
Just because somebody writes an expression down wrong, does not make my answer to the equation which is written down incorrect. Similarly to somebody using their or there or they're.... Incorrect usage does not alter the meaning and therefore correct answer.

If the person (correctly or incorrectly) writes 1 + 2 x 3 then the answer is ALWAYS = 7!! If said person actually mean to write (1 + 2) x 3 = (which would be 9) then it is their writing of said term that is incorrect, however I am answering what is written, so 7 would ALWAYS be correct, however many times you may argue otherwise.

The use of brackets to clarify meaning is only necessary when the meaning is anything other than the standard one.

Now, could somebody please find me the square root of  -36 ... this is where it gets fun!
Posted 29 July 2013
tonycsm
Photographer
tonycsm
Interestingly, if those of you who are using Windows bring up the 'Standard' calculator and input 1 + 2 x 3 then the answer will be 9.
However if you bring up the calculator and select 'Scientific' and input the same expression, the answer comes up as '7'!

The latter must be one of those ignorant and mechanical calculators I have heard about!
Posted 29 July 2013
Edited by tonycsm 29 July 2013
To reply to this thread you must be a member. Click here to join