Struggling with Math

I'm waiting for the answer to your first question as well.

It sort of looks like the reverse of Add.Subtract.Multiply.Divide.Parentheses which I learned as the order in which to perform operations...

And you're definitely right that the correct use of units is basic to science and engineering.

I was always taught My Dear Aunt Sadie with Parens from innermost to outermost as the correct progression.

I don't have a clue what the B and O are.

Hooker

BOMDAS is simply the order of working a mathematical problem. First work any and all brackets (B) Next, work any of's like half of 8 (O), Multiply, Divide, Add, Subtract. That was the way we were taught in school many decades ago.

It now has been changed to BODMAS. This reverses the order of multiply and divide. I haven't tried a theoretical problem to see if this makes a difference, but if not, then why change a system that worked.? 1+1=2 ? Purely a grade 1 sum.

Rod.

The only thing I can think of is the possibility of dividing by zero. Arithmetic cannot cope with this division so one should test for this early.

Hi redfred, quite correct. Divide by zero and the answer is infinity, strictly a no go zone. multiply by zero and the answer is zero.

Rod

These days, the mnemonic is more often expressed as "PEMDAS" (parentheses, exponents, multiplication, division, addition, subtraction). That forgets concatenation, which may fit best between E and M. (I would have to reexamine to be sure.) There are various Internet controversies about this.

Certainly if you want to excel in math, my advise is, account all your credit and financial expenses everyday. Then, you got to grasp the real sense of those numbers. Carpentry, masonry, earning a living and gardening sometimes help you figure out.

Some say counting beans may help, but you rather not.

I’m so surprised we had to complicate such a simple concept with an acronym. I was never taught an acronym. I was simply taught to do whatever’s in parenthesis 1’st, then multiplication or division (didn’t matter which) and the add or subtraction last (didn’t matter which). I never heard of BODMAS or PEMDAS & had to google it to find out. So giving credit to “technophile” from my google search:

The order of division and multiplication doesn't matter; 5 / 2 * 3 is the same as 5 * 3 / 2. Whether you divide by two or multiply by 3 first, you still get 7.5. If you get a different answer via PEMDAS than you do using BODMAS then you applied one of them incorrectly.

(As an aside, it's the same story with addition and subtraction; 3 - 1 + 2 = 3 + 2 - 1.)

So MD vs DM is irrelevant; both are equally correct as they both give the same answer. They have the same priority; the convention generally is we apply them left-to-right, not in any particular multiplication-before-division (or vice versa) order.

In both cases the order doesn't matter because they are simply inverse operations; you can express all subtractions as negative additions, just like you can express all divisions as fractional multiplications. So you can rephrase 5 / 2 * 3 as 5 * (1/2) * 3, or 3 - 1 + 2 as 3 + (-1) + 2, and since multiplication and addition are commutative you can then rearrange and apply them in any order you like.

Why don't you just try to solve 3/xy unambiguously? And then learn about the aforementioned concatenation. There is some pontificating Internet character from India who seems to know nothing about this.

Off Topic? Pontifying?

3/xy is poorly written in my book & as written leaves room for confusion. Brackets are clearly needed in such a case.

Written properly you've either got (3/x)*y or 3/(xy).

I'm outta CR4 forever. I don't need this.

When I learned this stuff, the terms used were associative and distributive presented as properties. Distributive included cases like (a+b)*c= (a*c)+(b*c). In this case, the brackets are essential and "good practice".

If you knew the properties, you didn't need acronyms.

Are they teaching properties any more?

I had trouble (and still do to some extent) in appreciating what 'properties' are by definition, but no problem in understanding the sequence of priorities for dealing with the 'numbers' - something I needed to help me remember BODMAS - not that I need to.

Much like help with the 'Hypotenuse theorem' ... Pythagoras squared equals the sum of the squares of the other two sides......

....but I imagine many of us have 'private' acronyms to help remember things.

That was a movie, right? "The Eternal Triangle" with Doris Day as Hypotenuse?

Que sera sera !

Hello Flash... assume X=3 & Y=5

Your first example 3/x*y could equal 3/3=1 multiplied by 5 =5

do the multiplication first. x*y= 15

3/15 =.2

This is the reason to have a set rule so the entire world will work the same math. the same way. I fail to see the reason people try to work things a different way.

Another writer called a straight math sum 1+1=some ridiculous answer. If I meant to have a sum with different things I would have written it that way. 1 apple plus 1 orange = 1 apple and 1 orange, not a fruit salad.

....what do calculators use...is it BODMAS or BOMDAS...both the same in human terms.

But different answers can be given without paying careful attention to the key sequence usually needing extra intermediate keys, 'reciprocal' or 'brackets' or 'equals'....much along the lines of basic math computer programming...

It's easy to misconstrue anything, especially in statistics. X's and Y's are obviously variables. But, even the numbers themselves can be variables (especially in statistics); they're an attempt to quantify abstract values by linking measurable/observable events with abstract causes/origins. It's not that simple. A lot of "statisticians" attempt to "prove" "scientifically" that "facts" are facts, when they're not. And they're one of the ones who're making that "fruit salad." That's why it's important to keep asking and answering the question "one what?" If you don't make a conscious effort to stay on-topic/on-the-same-page, many participants could end up in the wrong ball-park playing the wrong game. Then you'll either have to abandon the conversation or ask, "what were we talking about again?"

Has anyone ever read Bertrand Russell's proof of 1+1=2. Though I want to I haven't.

The proof is spread across the two volumes of Alfred North Whitehead and Bertrand Russel's text "Principia Mathematica". The desire for such a proof is expressed in Volume 1 page 379 while the actual proof is found in Volume 2 page 86. Bertrand Russel was certainly correct that this proposition is occasionally useful.

_{{Good Luck with the operator symbols.}}

_{{Good Luck with the operator symbols.}}

I can see that... they should update the print to a more modern font format.

So what could 1 + 1 = 2 have been before Bertrand Russel ?

A plausible assumption.

Less than a handful.

Way back when I was in elementary/secondary schools (in the ''dark'' ages ?...), back when teachers actually wanted us to ask serious questions, classes were mostly taught by being primarily directed towards what they thought was a standardized ''norm'', so that most of the students could understand most of what was being taught, most of the time, because they essentially only had enough time to teach one way, and still cover enough subject matter to meet the academic standards of the times... I think they intuitively knew there was such a thing as some sort of (mental dexterity ?), and that there was at least (right-handed (ie:quantitative) understanding) and (left-handed (ie:qualitative) understanding), and that there were all-manner of percentages in between, so they just tried to take their ''best shot'' at something in the middle, while maintaining a semblance of order in the classroom...

As for modern day colleges, except for political-science/sociology/etc., classes they clearly aren't assigning anywhere near enough class-relevant homework...

The ''catch'' being that, for college political-science/sociology/etc. classes, violent protests and disruptive activity are now considered as relevant class homework...

Way back when I was in elementary/secondary schools (in the ''dark'' ages ?...), back when teachers actually wanted us to ask serious questions,

Even back then there was a bias,... In elementary school (5th grade as I recall), when we would be talking politics in our social studies, anything that resembled a conservative viewpoint during the discussion was quickly put down, by either talking down to the person, belittling them or discipline them... and this bias would continued on to the next subjects. (We had one teacher that taught all the subjects)

Later on it made sense why this happens, mostly when the teacher returned from the teachers conventions and I'd overhear their discussion in the lounge. (It appears they would all be at the conventions to agreed with each other.)

Thank god I persevered and survived.

(sarcastically): Vatt!? Vee can not haff such indepent thinkink!!! You must immediately go undt vacation undt vatch CNN and/or MSNBC for 24 hours per day, straight, for two, full veeks, minimun, undtill you see zhe correct light. Why do you think we call it ''programming'', anyvay?... Vee Demo-Socialists vill be vatching you, from now on...