Vagabond

joined 1 year ago
[–] Vagabond@kbin.social 8 points 11 months ago (6 children)

I see what you're getting at but the issue isn't really the assumed multiplication symbol and it's priority. It's the fact that when there is implicit multiplication present in an algebraic expression, and really best practice for any math above algebra, you should never use the '÷' symbol. You need to represent the division as a numerator and denominator which gets rid of any ambiguity since the problem will explicitly show whether (2+2) is modifying the numerator or denominator. Honestly after 7th grade I can't say I ever saw a '÷' being used and I guess this is why.

That said, I'll die on a hill that this is 16.

[–] Vagabond@kbin.social 4 points 11 months ago* (last edited 11 months ago) (1 children)

Ah sorry just realized what you were saying. I've never been taught that. Maybe it's just a difference in teaching styles, but it shouldn't be since it can actually change the outcome. The way I was always taught was if you see a number butted up against an expression in parentheses you assume there is a multiplication symbol there.

So you were taught that 2(2+2) == (2(2+2))
I was taught 2(2+2)==2*(2+2)

Interesting difference though because again, assuming invisible parentheses can really change up how a problem is done.

Edit: looks like theshatterstone54's comment assumed a multiplication symbol as well.

[–] Vagabond@kbin.social 15 points 11 months ago (6 children)

Not quite. It's true you resolve what's inside the parentheses first, giving you. 8÷2(4) or 8÷2x4.
Now this is what gets most people. Even though Multiplication technically comes before Division the Acronym PEMDAS, that's really just to make it sound correct phonetically. Really they have equal priority in the order of operations and the appropriate way to resolve the problem is to work from left to right solving each multiplication or division sign as you encounter them. Giving you 16. Same for addition and subtraction.

So basically the true order of operations is:

  1. Work left to right solving anything inside parentheses
  2. Work left to right solving any exponentials
  3. Work left to right solving any multiplication or division
  4. Work left to right solving any addition or subtraction

Source: Mechanical Engineering degree so an unfortunate amount of my life spent in math and physics classes.

[–] Vagabond@kbin.social 16 points 11 months ago (81 children)

8÷2(2+2) comes out to 16, not 1.

Saw it posted on Instagram or Facebook or somewhere and all of the top comments were saying 1. Any comment saying 16 had tons of comments ironically telling that person to go back to first grade and calling them stupid.

[–] Vagabond@kbin.social 1 points 1 year ago* (last edited 1 year ago)

He sure did! And yeah, that's pretty much how I felt about his beliefs. If everything is decided already, then there's no point in having any motivation to do anything because it won't matter. Your destination is decided no matter what, so just do whatever you want regardless of if it's morally just or not.

[–] Vagabond@kbin.social 1 points 1 year ago

It sounds like you know more than this about me so correct me if I'm wrong but my understanding is there's a difference between just plain omniscience (which sounds like what you're describing in your comment, and is pretty widely accepted among Christian denominations) and actual predestination (which to my understanding is almost exclusively a Calvinist belief).

[–] Vagabond@kbin.social 0 points 1 year ago (4 children)

I had a teacher in school who believed in predestination. Basically, whether you go to heaven or hell is pre-ordained before your even born and there's nothing you can do to change it. I told him that sounded to me like I should be a Satanist because if I'm predestined for heaven I've worshipped Satan all my life for nothing and I get to chill in heaven. If I'm predestined to go to hell I've spent so much time worshipping Satan it probably won't be too bad. I'm personally not really religious myself but I really was dumbfounded at the whole predestination thing.