Discussion in 'Debate & Marathon Threads Archive' started by DrivingPigeon, Apr 6, 2015.

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1. ### DrivingPigeonPhenom

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Apr 6, 2015

Uhhh...I didn't know how to do the division symbol. I thought about explaining that the / was in place of the division symbol, but I assumed people would just figure it out. And they did.

But thanks for all of that.

2. ### czaczaMultitudinous

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Apr 6, 2015

:lol:

I've never thought about a keyboard not having the 'division sign', but good we understood what you meant.

3. ### TeacherGroupieModerator

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Apr 6, 2015

It can be disconcerting when a story turns out to be less cut and dried than one thought, yes.

Turns out, by the way, that the notation that we all grew up with for long division is really rather recent - enough so that the sign for it (which looks like it was cobbled together from a left parenthesis attached to a horizontal line, because it WAS cobbled together from a left parenthesis attached to a horizontal line) doesn't have its own name. See http://jeff560.tripod.com/operation.html.

4. ### vickilynMagnifico

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Apr 6, 2015

Wow, I thought I was the only person not seeing it as clear cut, and now I can understand why. I truly thank you.

5. ### brosPhenom

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Apr 7, 2015

Order of Operations might be taught that early now. I was taught it in eighth grade (Pre-Algebra, or at least that was what was taught at the time).

Because I couldn't figure that out mentally. Last time I had to do any kind of rigorous mental math was my neuropsych eval in 2010, before that, sometime in high school when we weren't allowed to use calculators.

If I were to try to solve it without a calculator, I would proceed as follows:
7+7/2*8-6
PEMDAS (Parentheses, Exponent, Multiplication, Division, Addition, Subtraction)

No P or E. so lets do M, as that is what comes first.

2*8

16
7+7/16-6

There's D

7/16 = 7/16

7+7/16-6

There's A
7+7/16 = 7 7/16

7 7/16-6

Now there's S

7 7/16-6

1 7/16

Yeeeeah

I have no idea how or why you can change the order of operations like that. It is PEMDAS, not PEDMAS.

alt+0247 (on the numpad) ÷ for windows users.

6. ### TeacherGroupieModerator

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Apr 7, 2015

Oh, and on a PC I bet Alt-/ (that is, Alt plus lower case question-mark) would work to type the obelus.

7. ### MikeTeachesMathDevotee

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Apr 7, 2015

PEMDAS and PEDMAS are the same thing. It's "multiplication or division, whichever comes first".

8. ### 3SonsConnoisseur

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Apr 7, 2015

I see M/D as essentially the same operation (albeit, inverse of each other). Similar with addition/subtraction.

The way I did the problem is by treating 7/2 as a fraction, multiplying it by 8 to get 56/2, and then dividing 56 by 2 to get 28 (in fact, you'd get the same answer, perhaps easier mentally, by dividing the 8 by 2 first to get 4, and then multiplying the 4 by 7). Then I add 7, and then subtract 6 (though I *could* have combined the +7 and -6 together and just added one).

Personally, I don't see the question as ambiguous. If there aren't parentheses, the 7+7 is NOT intended to be grouped over the 2 (it may be because of my background in computer programming, where formula HAVE to use the virgule and the computer will quite clearly use the OoO as defined within its math guts, to do the problem).

9. ### czaczaMultitudinous

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Apr 7, 2015

Aspects of order of operations are taught in grade three. NOT all of PEMDAS. For example, third graders solve word problems requiring them to use multiple operations and write equations to solve. They are also using beginning algebra concepts in some activities. Definitely 4th and definitely in 5th, students are pretty much using PEMDAS as shown here (albeit with the regular division sign in most cases)

A bit off topic, but did you take any math in college, or as part of teacher preparation? I transferred my license from Virginia so I'm unclear of what Praxis are required in our state, but do NJ teachers take the math Praxis as part of certification?

10. ### 3SonsConnoisseur

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Apr 7, 2015

Not sure this has anything to do with common core, but maybe it should:

A bat and ball cost \$1.10.

The bat costs one dollar more than the ball.

How much does the ball cost?

11. ### czaczaMultitudinous

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Apr 7, 2015

PEMDAS is not exclusively common core, nor is problem solving. Both types of math concepts existed way before CCSS.

12. ### gr3teacherPhenom

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Apr 7, 2015

It should really be:
P
E
MD
AS

Basically, multiplication and division are done in order, as are addition and subtraction. You work from left to right, doing them in the order they come up.

13. ### amakayeEnthusiast

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Apr 7, 2015

I didn't know it didn't have an official name. When I was in elementary school, it was called a "division box", and that's the same name that the math series I teach uses (in another region of the country, interestingly).

14. ### czaczaMultitudinous

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Apr 7, 2015

Just for fun I call it the goesinto sign! As in 4 goes into 28 :lol:

However, I teach my kids how problems are set up in different ways and how to navigate through and problem solve regardless of how an equation is set up.

15. ### Ms.BlankCompanion

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Apr 7, 2015

hmy:

Bros, I really don't mean to be offensive here, but someone else asked what I'm thinking...how did you get through a bachelor's program AND and teaching credential program without ever hitting (and fully comprehending) the order of operations? Even if you DID first approach them fully at eighth grade, you've had more than enough time to master the concept. Could this be a component in your troubling job search? Are you teaching something to do with this during demo lessons, have a reference who is telling prospective employers that your math foundation isn't solid, SOMETHING? Just a thought, maybe something to look into... The others are right, the schools I work in are working with the full range of order of operations in fifth grade, with smaller parts of this concept being taught all the way up until then (meaning this is something that you, as an elementary school educator, should be very familiar with...I am NOT saying that just because now they are working with it in elementary, that means you should have learned it in elementary...please don't twist my point around).

Honestly, I'd be furious if I had sixth graders come to my classroom after having a fifth grade teacher that taught them that multiplication MUST come before division and addition MUST come before subtraction...because it doesn't work that way. It would be a LOT of reteaching on my part. Order of operations is a HUGE concept...one that is built upon and used well into high college level math (and the rest of one's math schooling and career). It's important. Without a proper foundation, the kids will suffer greatly.