Add new comment
-
Want facts and want them fast? Our Maths in a minute series explores key mathematical concepts in just a few words.
Generating electricity without the use of fossil fuels is not just an engineering and industrial challenge, it is also a huge mathematical challenge.
In this podcast author Coralie Colmez shares insights into her novel The irrational diary of Clara Valentine.
We talk to early career mathematicians who spent some of their summer holiday solving problems posed by industry — such as how to blend a perfect smoothie!
Don't like plant-based meat alternatives, but want to spare animals and the environment? There's hope on the horizon, aided by a good helping of maths.
Inverse problems are mathematical detective problems. They can help solve crimes, are used in medical imaging, and much more.
The problem is that many people "glue" 2 and (2+1) together, treating it as a unity and in that way putting their relationship, in terms of priority, before the commonly accepted order of operation.
In other words, they don't treat it as:
' something...2*(2+1) ' ,
but as
' something...[2*(2+1)] ' ,
which causes the problem here.
You can't just, out of nowhere, look at '2' and '(1+2)', ignoring the relationship in which '6' is with '2', and use left-distributive property here, because you go out of the order of operations.
I think it's commonly accepted that 'xy' means 'x*y' and should be treated as such, followed by treating operation of division and multiplication with equal priority, going from left to right.
If you assume otherwise and put the priority of multiplication, even with omitted * sign, before the other operations, then you are actually and indeed making a small mistake here, assuming something that is out of convention.
So, I think that '9' is indeed the correct answer and the other way of thinking IS NOT equivalent - maybe not in obvious way, but it's disregarding the order of operations and treats unmarked 'xy' multiplication not as 'x*y', but as '(x*y)' , discretely "adding brackets"!! :-)