(* (+ 2 5) (- 8 5))
Hope some LISP can clear this up
this post was submitted on 27 Nov 2025
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Is this a meme? Shouldn't it be
( + 2 ( * 5 ( - 8 5 ) ) )
Explain yourself sir
This is called "prefix notation". The operator comes before the operands and every expression goes in parentheses.
For instance you could write:
(+ 1 2 3 4)
Which would evaluate to 10.
This syntax is from a family of programming languages usually called LISP.
But 2 + 5 + 8 - 5 is 16 - 5 which is 11
Gotta distribute:
2+(8+5)-(5+5)
2+13-0
15
Still not how distribution works. That would be:
2+((8 * 5)-(5 * 5))
2+(40-25)
2+(15)
17
Anything other than 17 is wrong. No matter how you go about your multiplication step.
You're trolling, but no, if you distribute you get the same result:
2 + 5(8 - 5) =
2 + (5 × 8) + (5 × -5) =
2 + (40) + (-25) =
2 + 40 - 25 = 2 + 15 = 17
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(1 replies)
Its because its:
2+5×(8−5)
My calculator app automatically added it when typing in what was in the image and "2+5×(8−5)" does equal 17.
It's absolutely the fault of the person making the social media media post for not writing it properly and confusing people.
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(2 replies)
Or it simply could be that I haven't needed to concern myself with the order of operations more than a dozen times since high school. Even when working as a web coder it was so seldom necessary that I can't recall a single example.
The US education system was still pretty decent when I was in middle and high school in the 1980s, so we definitely covered this in algebra.
I haven't had to do this shit in 20 years since college. Literally nothing like this in my career path, I was shit at math in high school and college,, so I didn't even remember that there was a multiplication there since it isn't explicit. Oh well.
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(4 replies)
it's
a badly
written
math
problem
Seriously, every time this comes up and everyone makes a huge deal out of it, I keep thinking, "none of the people writing these better be teachers." You have to be more clear than this.
how should it have been written?
I think it's reasonable if you consider the kind of physical situation it might represent.
You visit a farm and there are 2 unpackaged apples. There are also 5 packages that hold 8 apples but 5 have been removed from each. How many apples are there?
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(2 replies)
That's so evil and subtle. It took me multiple attempts to figure it out. You have to have quite the sharp eye to realize: no, you do not stop at calculating the numbers in parantesis first. You don't add the resulting numbers, there is no +/- operator, so the number in parantesis is the power of the number before it. But wait! if You calculated 2+5 = 7 * 3 and hot 21, you are wrong. Remember that multiplication goes first, so it's: 2+5(8-5) = 2+5*3=2+15=17
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(2 replies)