Mistic

We teach the fundamentals

Sure. They are, however, not the focus. At least that's not how I've been taught in school. You're not teaching kids how to prove the quadratic formula, do you? No, you teach them how to use it instead. The goal here is different.

They only teach order of operations.

Again, with the order of operations. It's not a thing. I've given you two examples that don't follow any.

The constructivist learners...

That's kinda random, but sure?

And many proofs of other rules...

They all derive from each other. Even those fundamental properties are. For example, commutation is used to prove identity.

But the order you apply operators does matter

2+2-2 = 4-2 = 2+0 = 0

2 operators, no order followed.

If we take your example

2+3×4 then it's not an order of operation that plays the role here. You have no property that would allow for (2+3)×4 to be equal 2+3×4

Look, 2+3×4 = 1+3×(2+2)+1 = 1+(6+6)+1 = 7+7 = 14

Is that not correct?

Notably you picked...

It literally has subtraction and distribution. I thought you taught math, no?

2-2 is 2 being, hear me out, subtracted from 2

Same with 2×(2-2), I can distribute the value so it becomes 4-4

No addition? Who cares, subtraction literally works the same, but in opposite direction. Same properties apply. Would you feel better if I wrote (2-2) as (1+1-2)? I think not.

Also, can you explain how is that cherry-picking? You only need one equation that is solvable out of order to prove order of operation not existing. One is conclusive enough. If I give you two or more, it doesn't add anything meaningful.

Yes we are

Yes and no. You teach how to solve equations, but not the fundamentals (and if you do then kudos to you, as it's not a trivial accomplishment). Fundamentals, most of the time, are taught in universities. It's so much easier that way, but doesn't mean it's right. People call it math, which is fair enough, but it's not really math in a sense that you don't understand the underlying principles.

Yes there is!

Nope.

There's only commutation, association, distribution, and identity. It doesn't matter in which order you apply any of those properties, the result will stay correct.

2×2×(2-1)/2 = 2×(4-2)/2 = 1×(4-2) = 4-2 = 2

As you can see, I didn't follow any particular order and still got the correct result. Because no basic principle was broken.

Or I could also go

2×2×(2-1)/2 = 4×(2-1)/2 = 4×(1-0.5) = 4×0.5 = 2

Same result. Completely different order, yet still correct.

My response to the rest goes back to the aforementioned.

Same in Russia.

"No to war" is considered "extremism," which is against the law.

You can also be charged for waving a blank piece of paper.

Wasn't it a kickstarter product? I wouldn't consider venture a pre-order, tbf.

Pre-orders are reservations with pre-payment.

Crowdfunding is, well, funding. You aren't buying a product. You're funding it, which comes with additional risks and benefits.

Of course, there's always a possibility that a product is being funded using pre-orders, which is financially irresponsible (norm varies from industry to industry). But you must be a moron to pre-order a product from a startup you know nothing about and expect not to get scammed. Outright buying their product would be risky enough.

Take housing market. You're pretty much always either pre-ordering or buying second-hand.

Pre-ordering physical goods is fine, especially if you expect a price hike and supply limitations after launch. I wouldn't, but I can see how it would make sense.

It's the digital goods that make no goddamn sense to buy before they're out. They're not limited in supply, and their return window is often too small.

That's because (strictly speaking) they aren't teaching math. They're teaching "tricks" to solve equations easier, which can lead to more confusion.

Like the PEMDAS thing that's being discussed here. There's no such thing as "order of operations" in math, but it's easier to teach by assuming that there is.

Edit: To the people downvoting: I want to hear your opinions. Do you think I'm wrong? If so, why?

The "why" goes a little further than that.

In actuality, it's because of fundamental properties of operations

• Commutation

a + b = b + a

a×b = b×a

• Association

(a + b) + c = a + (b + c)

(a×b)×c = a×(b×c)

• Identity

a + 0 = a

a×1 = a

If you know that, then PEMDAS and such are useless because they're derived from those properties but do not fully encompass them.

Eg.

3×2×(2+2) = 3×(4+4) = 12+12 = 24

This is a correct solution that is improper if you're strictly adhering to PEMDAS rule as I've done multiplication before parenthesis from right to left.

I could even go completely out of order by doing 3×2×(2+2) = 2×(6+6) and it will still be correct

Oh yeah, that's a fun one.

Where I live, this would be considered juxtaposition, at least by uni professors and scientific community, so 2(4-2) isn't the same as 2×(4-2), even though on their own they're equal.

This way, equations such as 15/2(4-2) end up with a definite solution.

So,

15/2(4-2) = 3.75

While

15/2×(4-2) = 15

Usually, however, it is obvious even without assuming juxtaposition because you can look at previous operations. Not to mention that it's most common with variables (Eg. "2x/3y").

I find it funny how your opinion could be described using the exact same words. Lol.

I was thinking of plane surfaces, but if their altitudes are different, I guess it'd be possible.

Wdym?

Equal sides in a triangle are only possible if the corners are equal. So, 60⁰ each.

But its height cannot be half of base because of the same Pythagorean theorem

(1,5)²+(1,5/2)²=2,8125

sqrt(2,8125) ≈ 1,677, which is half of a diagonal

So, we get 4 sides that are 1,5 in a parallelogram, but diagonals are 1,5 and 3,354, as opposed to both being 1,5 as shown on the picture

TL;DR: Won't work because Pythagorean theorem