Possibly they are testing where the parents' skills lie and not the child's

23-1(4+9){or, 23-(4+9}=23-4-9=23-13=10
23-4+9=19+9=28
Artificially inserting a set of brackets or parentheses where they aren't specifically expressed leads to the wrong (+/-) being assigned to the individual units. Copago, you seem to insert brackets on your own to separate out the steps as you perform them. This can lead to errors. In the first example above the negative sign is applied across the board into the parentheses, changing a plus 4 to a negative 4 and a plus nine into a negative 9. when it is only the 4 unit that is negative. Once all brackets, exponents and multiply/divides have been done and you are left with only +/-, work left to right, addding and subtracting (whichever is called for in order) as you go.

Thanks everyone for explaining the rule. I imagine I learned it once upon a time, but it's so far back in the distant mists of elementary school that I have no memory of it.

Looking back on these posts I've just realized something...how young the kids are that are learning this. My first exposure to PEMDAS was in 7th grade algebra (1st year of middle school). 10 years old seems awfully young to me to be learning such things. I was in the highest level of math that my school district offered for my grade (advanced programs since 4th grade/9yo) and I was young for my class. I didn't even get it until I was 12. Some people didn't even get Algebra until 9th grade/freshman year of high school. Maybe they just start teaching things at a later age in the US than they do in Australia...

I remember learning it in primary school (somewhere between year 5 and 7 - which is about 10-12 years old). I learnt it as BIMDAS though. Nothing has changed (except what people are calling it) it's just difficult to explain concepts to your kids if you aren't entirely sure of it yourself.

I feel sorry for those parents who struggled in school and now have to try to explain some of these things to their own kids.

"it's just difficult to explain concepts to your kids if you aren't entirely sure of it yourself. "

Oh God, isn't that the truth?!?

As I said to the teacher .. going soley on that page I posted up there it doesn't say anything about Multiplication and Division together or additon and Subtraction.. just that it should be done in a specific order which is what confused me. I took it too literally.
And I just flat out said I'm not gettting him to work something out a "wrong way".

I am willing to bet that this doesn't come up for a while again in his work .. which does annoy me somewhat. If pressed the teacher would say we are just "exposing" them to it for teaching at a later stage. it seems to be a common answer.

It's funny this has come up as a topic for discussion right now, as my oldest grandchild, a 10 year old boy in 5th grade, was struggling with his math homework today. He brought it to his mom, my oldest daughter, who majored in theatre at University and thinks math is Satan! She took one look at it, said, "That's algebra! Go talk to your stepdad. I don't do algebra!"

÷

Hold down Alt key and type 0247

Knew it would be there somewhere .. Thanks Sue.

lol Jabb It's not that I think Maths is Satan but, after this, it's certainly hanging out with him.

Alt and 0247 on my computer gives me a string of a bunch of symbols: º™¢¶. To get the ÷ symbol I have to type Alt and the / key. I have a Mac.

That last sentence says it all.

They should just have a key for it .. and one for the most common fractions too come to that.

I have another question for anyone still coming in ..
What would 3.25 hours mean to you?
3 hours and 15 minutes or three hours and 25 minutes?

It would definitely be great if there was a key that had the ÷ key on it.

I read it as 3.25 hours to be 3 hours 15 minutes. 3.25 as in 3 and 1/4 hrs. Usually when I want to write 3 hrs and 25 minutes (like for keeping time at work) I will write 3h25, which is just as fast as 3.25 to write, but not as confusing to me when I go back to look later. I use .25, .5, and .75 to me 15mins, 30mins, and 45mins, but if I have a weird time, I'll write h05, or h40, or h35, just so I don't confuse myself!

I would think that 3.25 means three and a quarter hours (3hr 15 mins). 3:25 would be twenty-five past three.

Another for three and a quarter.

Three and a quarter hours.

yep

When I was in school, I was shuffled through grade to grade without understanding math. I didn’t, nor do I now, have the patience before it. Whenever I see an equation, I get a headache (although I do seem to remember in my last year or so of high school that somebody finally thought to give me extra support in that subject—and I went from getting Ds to Bs.

When I took math in college, I had to take prerequisites—and failed the first time I took it (this was bef ore I realized that a D constituted a failing grade). I had to repay to take the course, switched to another instructor (who had a reputation around campus as being “great,”) and got an A or a B (I don’t remember which offhand).

My problem has always been compounded by the way math equations (and graphs) are portrayed in Braille (depending on the type of graph, it needed an interpreter—and as for the equations… and one math book was at least 28 Braille volumes!) Anyone surprised I routinely fell behind?

There’s something fundamentally wrong with a school system that teaches students this way

The boundaries to my back property line are 11.33 feet (expressed as 11.33' on the plat) from the back of the structure. There is a utility easement in the last five of that footage. My neighbor also has a five foot easement on his side of the line. He did some building in that five foot meaning any utility work would be essentially forced to take place on my property and not fairly on his too. I filed a complaint (it is legally called encroachment). The Committee responsible for enforcing those rules sent out a woman who read the plat as saying my property went 11 feet thirty three inches in back of my house. How can someone who needs to make decisions about property lines not know that if 11 feet 33 inches was what was real it would have been expressed in whole feet and fractions of a foot and not whole feet and multiples of feet? Eleven point three three feet turned into 11 feet 33 inches to this arbiter and so she measured 13 feet 9 inches back from my house to find where the property divide was. "Well you filed a valid complaint because this work has been done on your property," she said!
When I told her that 11.33' meant 11 and a third feet or 11'4" and she went to remeasure, she then tried to tell me my property line only went back 6.33 feet because the utilities companies owned the land the easement was on. I then had to explain that I paid taxes on the 11.33' and that the easement meant I owned the land but ceeded certain activities on my land could be performed by the utilities. She just shut up and left. I went to the office to ask why they sent such an unknowledgable person on such a job. I heard crying and arguing coming from an office down the hallway as I stood at the front desk. It was her as I saw from the front desk when she left the office where the disturbance was. She then accused me of sneaking around and eavesdropping as she reported her findings. She recommended not to find in my favor. Seems when people are shown they are wrong, they'll go that extra mile to make your life miserable.
I can fully appreciate the problem that 3.25 hours can present to people who know and need correct interpretation of time statements by someone who does not understand fractional notation.

You could probably guess this but the answer was 3 hours and 25 minutes.
*sigh*
the question was something along the lines of adding 3.25 hours to six thirty. i think the kids were supposed to guess that "six thirty" meant that it was a digital clock and that 3.25 on a digital clock is 3 hours and twenty five minutes. I still think it's 'wrong' even after the answer was explained.

Then it ought to have had a colon, not a fullstop.

Agreed, 3:25 means Twenty-five minutes past Three O'Clock but I've never seen that notation to mean three hours and twenty-five minutes. The notation 3.25 means three and a quarter hours. The only way I know to express Three hours and twenty-five minutes in just numbers and punctuation is 3 5/12 hrs. There is no decimally exact way to express it.
Note there is a similar method used in baseball when recording the number of outs a pitcher records. Since an inning has three outs and you want to say that he (sorry ladies) pitched 2 and two-thirds (2.666...) the current convention is to state it as 2.2 innings, Two point three innings would be the same as three point zero innings, So, the types of notion you'd see in a statistics list for baseball pitchers would all end in point zero, one or two. It makes sense in the context if you know the convention. In the time problem, the convention of twenty-five minutes being expressed as point two five flies in the face of the convention widely accepted that point two five equals a quarter hour and nothing else.

3.416 (the 6 needs a bar over it) would be decimally correct.

I cannot fathom going through math that is systematically incorrect.

I am a diehard for the use of a colon in times. Here is Australia, it has become standard practice to use a full stop (no shift key needed) in printed documents, but I retype every document I get my hands on to change it to a colon. As a maths teacher, I want that decimal point to have a consistent meaning. Of course, the universal practice of showing the cricket progress scores in terms of how many overs have been bowled using a full stop (when the number that follows is out of a maximum of 6) totally undermines my position in the adolescent mind.

A maths teacher! Please pass by here often, Looney - I'm sure I'll be needing more help along the way!