You get a pass on pretty much every subject because the school's interested in churning out worker drones rather than thinkers. Do this long enough and you get Trump supporters.
Practice is important. People definitely learn this level of math, but not using it for years dulls the senses. On top of that, lots of people scrape through school doing the bare minimum. (Not always their fault of course. Not everyone has ample opportunity to excel in school due to a variety of things.) From what I hear, the bar for graduating high school is not incredibly high, so people like this don’t surprise me.
Knowing basic math (and sometimes a bit more) is quite useful in life. I am currently having a beef with my bank who tried to cheat me out of a larger sum. But I know the correct methods and the correct rates, and, of course, the contract. And obviously, it really pisses them off that someone even does the calculations...
They teach math from like 6th grade up as if every middle schooler in the land is going to grow up to be a sweater wearing chalkboard writing mathematician when they grow up. It's taught as a series of arbitrary rules to follow. Here's some squiggles, and now you do this to the squiggles. NO you don't do that to the squiggles, do you want to be a ditch digger you fucking waste of sperm. You do THIS to the squiggles. Can't you FUCKING tell the difference you little cuntpuke? You use the Crendicative property of intiplicity. No, it's not five, it's negative three. It's obviously negative three, What idiot would get five? I know you got five and not some other number because this is designed to be a trick question. There's only one point in this big long procedure that matters, if you decide correctly you get negative three, if you decide incorrectly you get five. And you got five.
Yeah you're right that they act like everyone's gonna be a pure mathematician with only abstract applications. I think test standards have kinda fucked with their expectations. I'm sorry you had bad math teachers. Many of them suck at explaining the subject and act like dicks. Get enough of them in school and it's easy to lose interest in something that's extremely practical to know later in life.
Some bureaucrats in Mexico City tried this years ago.
An important ring road had two lanes in each direction. To increase its capacity, they didn't actually widen the road; they just repainted the lane markings to turn two lanes into three, and claimed a 50% capacity increase!
Everyone immediately screamed about being crammed together just centimetres apart, accidents increased and the city officials quickly u-turned; they repainted to have just 2 lanes in each direction again.
But they then tried to claim that as that was a 33% decrease, and that because they had earlier increased it 50%, that meant they had achieved a net 17% increase in the road's capacity!
While the idea put forward by him is correct, stating that 100-10=90+9=99 is just entirely incorrect, hence why I'm saying they're both somewhat correct
I might as well throw the same comment in here.
You learn this pretty quickly when you bet on meme stocks. Down 90% then up 100%
I can assure you, you are no where near where you started.
Same with crypto. You'll get a notification something went down 10%, then up again 10%, but if you zoom out you see it's just been slowly going down on average since the last huge spike.
This is why in forecasting and time series analysis is used the log difference, a 10% increase or decrease on the log scale gives you the same value being added or removed.