Understanding PEMDAS in Math: Is There an Exception?

  • Thread starter Petenerd
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In summary, the conversation discusses a question on an assessment that asked for x+3/3 with x=3. The confusion arose when the answer key showed the answer to be 2 instead of 4, which follows PEMDAS. The conversation also touches upon the use of PEMDAS and the importance of clear and accurate question writing.
  • #1
Petenerd
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On my assesment it had a question that said x+3/3, when x=3. I thought you do 3/3 first so did the teacher, but when he looke at the answer key it showed you were suppose to do 3+3 then divide by 3. And also on my test booklet, it doesn't have 4 which is the answer if you do it with PEMDAS. Instead they have 2, the answer you get when you add first... :?: Isn't that weird? The same thing happened on my state test. On one of the sample answers the state test gives a question just like that and when my teacher and the student found out the answer on the answer key, the answer only works if you add the two number then divide. And also the state test doesn't offer you the answer you'll get when you do it with PEMDAS. Who's right and who's wrong and what is the correct way to do this? :|
 
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  • #2


Division always happens before addition unless parentheses change the order. If they want addition first it should be written
(x+3)/3
or
[tex]\frac{x+3}{3}.[/tex]

I'm not entirely sure I like the abbreviation PEMDAS, though. The order is
P
E
MD
AS
which could easily be forgotten in that form.
 
  • #3


The funny thing is on the sample answer it doesn't follow PEMDAS. Do you think the other questions like that will follow PEMDAS? Because when I followed PEMDAS to do the problem, there wasn't a choice for my answer which was 4. :uhh:
 
  • #4


Petenerd said:
Do you think the other questions like that will follow PEMDAS?

Yes. I think it's more likely that the question was changed but not the answer, then that someone used the wrong order of operations in setting up the question. (This actually happens more than you realize!)
 
  • #5


I think I got the hang of this now!
 
  • #6


Petenerd said:
On my assesment it had a question that said x+3/3
Just checking... that is exactly what the problem said, right? The expression was

[tex]x + 3 / 3[/tex]

and it was not

[tex](x + 3) / 3[/tex]

and it was not

[tex]\frac{x+3}{3}[/tex]

?
 
  • #7


I think the question meant [tex]\frac{x+3}{3}[/tex], instead of [tex]x+\frac{3}{3}[/tex].
 
  • #8


If the question meant this [tex]\frac{x+3}{3}[/tex], I would add first then divide?
 
  • #9


Petenerd said:
If the question meant this [tex]\frac{x+3}{3}[/tex], I would add first then divide?

Yes.
 
  • #10


i think that unless the assessment is to test PEMDAS (first time i heard of that actually), then giving something like x+3/3 is just lazy. however, if i was given that, i would have assumed it meant (x+3)/3. no reason why someone would actually put 3/3 in an equation unless the intention was to trick.
 
  • #11


Thanks for the help! :)
 

1. What is PEMDAS and why is it important in math?

PEMDAS is an acronym for the order of operations in math: Parentheses, Exponents, Multiplication and Division, Addition and Subtraction. It is important because it provides a set of rules to follow when solving mathematical expressions to avoid ambiguity and ensure the correct answer is obtained.

2. Is there an exception to the PEMDAS rule?

Yes, there is an exception to the PEMDAS rule. When a mathematical expression contains both multiplication and division or addition and subtraction, they should be solved from left to right.

3. How can I remember the order of operations in PEMDAS?

A common mnemonic device to remember the order of operations in PEMDAS is "Please Excuse My Dear Aunt Sally" where each word represents the first letter of the operation in PEMDAS.

4. Can I change the order of operations in PEMDAS?

No, the order of operations in PEMDAS cannot be changed as it is a set of rules that are universally accepted in math to ensure consistency in solving mathematical expressions.

5. What happens if I don't follow the order of operations in PEMDAS?

If the order of operations in PEMDAS is not followed, the solution to a mathematical expression may be incorrect. This can lead to errors in calculations and potentially affect the overall accuracy of a problem or equation.

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