I cringe at those basic math question posted on the web.

For example

• 1 + 1 + 1 + 1 - 1 + 1 + 1 * 0
• 3 + 3 * 3 - 3 + 3
• 3 + 3 / 3 + 3

or this

3 * 3 - 3 * 0

-----------------

3 + 3

List goes on. I cringe because there are tons of people getting it wrong. ---___---

Some people are poor at maths. Some people are poor with language. Others lack basic social skills. Everybody sucks at something. 

Lots of people just don't remember the operator order, which is hardly surprising since it's not something most people actually need very often.

It's not helped by the fact that 99% of non-scientific calculators don't take the order into account either and would therefore give the wrong answer on those problems if they're typed as-is.

Most people don't know what word / words to use for their search terms on the internet.

Operator precedence works nicely:

http://en.wikipedia.org/wiki/Operator_precedence

36 minutes ago, Bas wrote

Everybody sucks at something. 

I have a couple of strengths that I have managed to capitalize on over the years, but I am well aware that I suck at *way* more things than I'm good (or at least passable) at.

@Proton2: I think basic "arithmetic operator ordering" has been taught in primary 3 when multiplication / division is taguht.

And for "it's not something most people actually need very often", I'd think it's the natural calculation sequence on your purchase reciept, just not many people who try to make connection from that daily fact. Once you make that connection you will remember it easily.

@cheong: Some of my earliest memories is being taught that anything multiplied by zero equals zero.

I still remember the Dutch mnemonic for the order: Meneer Van Dalen Wacht Op Antwoord

Machtsverheffen (powers)
Vermenigvuldigen (multiplication)
Delen (division)
Worteltrekken (roots)
Optellen (addition)
Aftrekken (subtraction)

@Sven Groot:

I stopped relying on mnemonics since I almost flunked a test for misremembering one.

Just curious, though: why should roots be computed after division?

@Blue Ink: Because it's an outdated mnemonic.  Powers and roots actually should have the same precedence. Apparently it used to be different in the past.

Not that I've ever seen an root without explicit precedence (without the top horizontal line) in the wild, so it's hardly a real problem.

According to the Dutch Wikipedia page on operator precedence, certain math textbooks maintained the old order (with upper line-less roots having lower precedence than multiplication/division) until the end of the 20th century. I guess the textbook that I used did so too, because I definitely remember being taught that mnemonic.

@Blue Ink: Kind people come over for good spaghetti. Anybody remember that one?

I've always found Roy G. Biv to be the dumbest mnemonic. It's actually easier to use the colors as a mnemonic for remembering the name than the other way around.

Music theory mnemonics are a close second. There are so many of them, many of them sharing the same words in a different order, that it's as hard to remember which mnemonic to use when as it is to just remember what they stand for. Especially the Dutch ones all seem to revolve about feeding monkeys.

See, I have a rhyme assisting. My feeble brain its chore resisting.

First 12 digits of PI. It's the only math related one I remember.

I don't know the first 12 digits of Pi, but I do know 0118 999 881 999 119 725...3 by heart.

Priorities...

@Sven Groot:

Good old BODMAS:

Brackets
Power Of
Division
Multiplication
Addition
Subtraction

Tbh, though, I think the whole thing is silly. If it's not immediately obvious what the order is, use brackets. Brackets are free, and readable code/math is always better than "clever" code or math.

1 minute ago, Sven Groot wrote

I don't know the first 12 digits of Pi, but I do know 0118 999 881 999 119 725...3 by heart.

Priorities...

For those that don't get the reference

@evildictaitor: I dislike those things. People start to say add before subtract because those things. I am like, dude, addition and subtraction has the same order.