Comment on A fake Facebook event disguised as a math problem has been one of its top posts for 6 months
Mistic@lemmy.world 1 month agoThat’s because 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 that there is.
SmartmanApps@programming.dev 3 weeks ago
Yes we are. Adults forgetting it is another matter altogether.
Yes there is! 😂
No, I know you’re wrong.
If you don’t solve binary operators before unary operators you get wrong answers. 2+3x4=14, not 20. 3x4=3+3+3+3 by definition
Mistic@lemmy.world 3 weeks ago
Yes and no. You teach how to solve equations, but not the fundamentals. Fundamentals, most of the time, are taught in universities. It’s easier that way, but doesn’t mean it’s right. People call it math, but it’s not really math
Nope.
There’s only commutation, association, distribution, and identity. It doesn’t matter in which order you apply any of these properties, the result will stay correct.
2×2×(2-2)/2 = 2×(4-4)/2 = 1×(4-4) = 4-4 = 0
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×(2-2)/2 = 4×(2-2)/2 = 4×(1-1) = 4×0 = 0
Same result, completely different order, yet still correct.
My response to the rest goes back to the aforementioned.
SmartmanApps@programming.dev 3 weeks ago
Nope. We teach the fundamentals. Adults not remembering them doesn’t mean they weren’t taught. Just pick up a Maths textbook. It’s all in there. Always has been.
No they’re not. They only teach order of operations from a remedial point of view. Most of them forget about The Distributive Law. I’ve seen multiple Professors be told by their students that they were wrong.
The Constructivist learners have no trouble at all understanding it.
Yep!
And many proofs of other rules, which you’ve decided to omit mentioning.
But the order you apply the operations does matter, hence the proven rules to be followed.
Notably you picked an example that has no addition, subtraction, or distribution in it. That’s called cherry-picking.
Yep, because you cherry-picked a simple example where it doesn’t matter. It’s never going to matter when you only pick operations which have the same precedence.
…cherry-picking.
Mistic@lemmy.world 3 weeks ago
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?
Again, with the order of operations. It’s not a thing. I’ve given you two examples that don’t follow any that are correct.
That’s kinda random, but sure?
They all derive from each other. Even those fundamental properties are. For example, commutation is used to prove identity.
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
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.