Math Is Fun Forum

JadeH

Member

Registered: 2016-10-07

Posts: 9

Order of operation changes???

First time making a post on this forum but i love the mathisfun site

ok on one of these silly facebook posts they ask
20+30x0+1=?
a)1
b)21
c)51
d)0

clearly by using "Please Excuse My Dear Aunt Sally" you get 21
20+(30x0)+1=
20+0+1=
20+1=

so i post "easy! b 21 Please Excuse My Dear Aunt Sally"

to what i get this reply....

"I understand your point, and according to "older" theory, the "30x0" would be the first operation in this equation. However, another similar equation has circulated in recent years in which mathematicians have explained that the order of operation has changed. In this new way, the order is based on the leftmost operator "20+30". The old standard would equate to "1", whereas the new standard would be "21". I think the entire math world is confused. LOL"

so my question is... is there any truth to this? it seems very far fetched

edited for a typo

Last edited by JadeH (2016-10-08 09:57:05)

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Order of operation changes???

Hi;

ok on one of these silly facebook posts they ask

Is there any other kind?

The smartest person on the internet and therefore the world ain't a person at all. It is the mighty Wolfram Alpha. Wiser than the Oracle at Delphi it is. So just go here...

http://www.wolframalpha.com/input/?i=20%2B30x0%2B1

You just keep using the PEMDAS.

"I understand your point, and according to "older" theory, the "30x0" would be the first operation in this equation. However, another similar equation has circulated in recent years in which mathematicians have explained that the order of operation has changed. In this new way, the order is based on the leftmost operator "20+30". The old standard would equate to "1", whereas the new standard would be "21". I think the entire math world is confused. LOL"

I understand your point...

Metatalk for listen you fool nobody knows what the heck you are babbling about but whatever it is, it is definitely incorrect. Somebody says that to me and we are alone in the wilderness, I slice open his gizzards and leave him for the gators...

Older theory? Now that makes my 96 year old nostrils flare. I guess he means math is a do what ever feels good sort of non threatening discipline. You know, like the way people mispell words nowadays.
Some programming languages use a strictly left to right evaluation but they have not replaced the way it is done in math. I use PEMDAS in calculations.

Welcome to the forum.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

zetafunc

Moderator

Registered: 2014-05-21

Posts: 2,436

Website

Re: Order of operation changes???

"I understand your point, and according to "older" theory, the "30x0" would be the first operation in this equation. However, another similar equation has circulated in recent years in which mathematicians have explained that the order of operation has changed. In this new way, the order is based on the leftmost operator "20+30". The old standard would equate to "1", whereas the new standard would be "21". I think the entire math world is confused. LOL"

Sounds like nonsense to me, especially when their justification is because "an equation" has somehow "explained" why we should change something which is a logical convention to begin with. The PEMDAS mnemonic you cite is our most common language for operation order -- if we didn't have it, we'd have to write expressions as something like this: (20 + ((30*0)+1)), assuming we use left-to-right scanner priority. On the other hand, you can invent whatever order of operations you like if you state that explicitly. The answer will still be correct with respect to their logical order of operations. But the standard is PEMDAS -- although really M and D are interchangeable, as are A and S, as long as you read left to right. If you want to avoid ambiguity in general then brackets are necessary, unless you have some order of operations which does not prioritise parentheses.

Last edited by zetafunc (2016-10-07 21:54:45)

JadeH

Member

Registered: 2016-10-07

Posts: 9

Re: Order of operation changes???

knew it couldnt be true so thank you both ^_^ just think of all the scientific calculators that would obsolete

i guess there really isnt anything other then silly posts on facebook! i more then anything wanted confirmation on this before "I slice open his gizzards and leave him for the gators" (can i nick that btw? that made me lol ^_^ )

doesnt seem like i can like posts on here or id of done so

again thank you both so much ^_^

lots of love jade <3

ps link to the mighty Wolfram Alpha saved for future use ^_^

Last edited by JadeH (2016-10-08 09:44:07)

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Order of operation changes???

(can i nick that btw? that made me lol ^_^ )

Sure, just remember I was kidding. Gizzard slicing is against the laws of God and man. We can not and should not ever use gizzard slicing. Let the gators find their own food. Also, be like the mighty Isaac Newton, rather than argue with people he kept silent for 20 years. Leave those with differing opinions alone, they will not change because we want them too, "we must cultivate our garden."

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

Matir

Member

Registered: 2016-10-08

Posts: 22

Re: Order of operation changes???

Tell that guy

"Please ask your question in reverse polish notation for unambiguous answers"

See if THAT drives him crazy... https://en.wikipedia.org/wiki/Reverse_Polish_notation

JadeH

Member

Registered: 2016-10-07

Posts: 9

Re: Order of operation changes???

just got the link to where this guy claims how to solve maths problems... http://www.slate.com/articles/health_and_science/science/2013/03/facebook_math_problem_why_pemdas_doesn_t_always_give_a_clear_answer.html

*facepalm*
so changing the sum to make your answer right... we now do this in math??? i dont think so!

ill stick to my pemdas!

Last edited by JadeH (2016-10-08 23:35:07)

JadeH

Member

Registered: 2016-10-07

Posts: 9

Re: Order of operation changes???

ok matir thats just confused the hell outta me lol

Matir

Member

Registered: 2016-10-08

Posts: 22

Re: Order of operation changes???

In fact postfix notation may just end all controversies over our conventional system, it is technically better than infix (at least for computers)

GilbertArias

Member

Registered: 2019-09-04

Posts: 1

Re: Order of operation changes???

Greg C. Since the "P" of PEMDAS is parentheses, I do not understand your comment "expressions like -(...) throw off those" following the order of operations expressed by PEMDAS. Insert any value inside the parentheses, and then reverse them, as the "P" rule dictates. Lets say (...) = (1 - 5). Then x -(...) = x -(1 - 5) = x + (-1) + (-(-5)) or x + (-1) + 5 or x + 4.

I actually read this post hoping to understand what BODMAS stands for. I get that Brackets replace Parentheses, and since the division IS multiplication, just as subtraction IS addition, there can be no distinction in the order of operations, provided we recall that subtraction of a positive number is equivalent to addition of a negative number, but what does the "O" stand for, that obviously must be equivalent to an exponent?

Reference from Pemdascalculator.com