Remember...PEMDAS

Please excuse my dear aunt sally

Remember...PEMDAS

Please excuse my dear aunt sally

Already been mentioned twice in the thread, but following PEMDAS strictly here gives the wrong answer, unless you remember (which I did not), that it's really P-E-MD-AS, with 'MD' being of equal precedent and 'AS' being of equal precedent, and apparently them being interpreted from left to right in the equation.

The conversation is interesting if you have the time to read the whole thread; leastwise, I found it interesting.

Thank the cripes alrighty no one here has studied remedial calculus where something like y = f(x) dx is the order of the day and suffers no preschool-level ambiguity at all.

Unless, I suppose, you want collect terms and rewrite that basic differential equation as y = dfx² er sumpin.

Already been mentioned twice in the thread, but following PEMDAS strictly here gives the wrong answer, unless you remember (which I did not), that it's really P-E-MD-AS, with 'MD' being of equal precedent and 'AS' being of equal precedent, and apparently them being interpreted from left to right in the equation.

To be fair, I've talked to people who said they were taught PEMDAS and being explicitly told by the teachers that precedence goes that way (i.e. no same precedence for any operations). Hey, the thread mentions some places teaching that implicit multiplication has higher precedence than explicit multiplication, so that isn't a stretch either :P

Reminds me something that confused me at elementary school, when we were taught division we wouldn't use ÷ but %... like um, what? That's a percent sign. There was no confusion in the calculations provided, but c'mon! Luckily in high school we'd be using : instead (which at least resembles ÷), while for multiplication either we'd use · or ditch the sign altogether.

Reminds me something that confused me at elementary school, when we were taught division we wouldn't use ÷ but %... like um, what? That's a percent sign. There was no confusion in the calculations provided, but c'mon! Luckily in high school we'd be using : instead (which at least resembles ÷), while for multiplication either we'd use · or ditch the sign altogether.

What symbols did you use for percentages and ratios?

Fun little addition to the mix. How about the distributive property?

Since the 6/2 is not grouped, we could rewrite it instead of implying it.

6 / 2 (1 + 2)
6 / (2 + 4)
6 / 6
1

Hey, the thread mentions some places teaching that implicit multiplication has higher precedence than explicit multiplication, so that isn't a stretch either

Except the implicit multiplication was a short hand used in some sectors because it made sense given the context there and it is still following the 'rules' of how math works, but just skipping some of the 'excess' notation. Strict ordering of PEMDAS however is just wrong.

Fun little addition to the mix. How about the distributive property?

Since the 6/2 is not grouped, we could rewrite it instead of implying it.

6 / 2 (1 + 2)
6 / (2 + 4)
6 / 6
1

Distributive property doesn't work that way because you've got the precedence wrong.

You still have to do the division first - and then you can distribute the resulting 3 to the rest of the equation.

Edit: How to correctly do the above if you want to use the distributive property:

6 / 2 * (1 + 2)
6 * 0.5 * (1 + 2)
6 * (0.5 + 1)
6 * (1.5)
9

I think the equation as written is ambiguous, there's no way of knowing whether it means (6/2)(1+2) or 6/(2(1+2)). If rewritten in code as 6/2*(1+2) I think every language I know of would interpret it as (6/2)*(1+2), giving the answer 9.

Reminds me something that confused me at elementary school, when we were taught division we wouldn't use ÷ but %... like um, what? That's a percent sign. There was no confusion in the calculations provided, but c'mon! Luckily in high school we'd be using : instead (which at least resembles ÷), while for multiplication either we'd use · or ditch the sign altogether.

What symbols did you use for percentages and ratios?

Elementary school, we weren't doing anything like that yet =P It still caused confusion to anybody who had a calculator though (since they usually have a percent button).

For the record, I'm pretty sure they were using % because it resembles a vulgar fraction (i.e. slanted bar - in the same way, ÷ resembles a fraction with a horizontal bar).