So, when you point out innumeracy I think you should explain it with patience. Explain it understanding that some people who may be well informed and intelligent in other matters might not understand why, for example, decreasing by more than 100 percent is nonsense.

(100 percent is all of something. A 50 percent decrease is half. '100 percent decrease means' it's zero. Decrease by more than 200 percent? means it's less than zero, negative. Negative prices make no sense. )

I agree.

Donald Trump is NOT a stupid man.

Really, he's not.

Okay sure, NOW he is struggling with dementia, but he's been playing fast and loose with numbers his whole career. It's a regular trait of con artists. It's like an anti-dog whistle to keep the attention of your marks and make them feel isolated from everyone else. To intentionally confuse use numbers to communicate facts with numbers to communicate vibes. For people like us who use numbers to communicate facts, we can't help ourselves but to go for the "Well Actually" when someone says "I'm going to lower prices 200%!" But for the people he's actually talking to, they understand what he's saying - "I'm going to lower prices a whole bunch".

@futurebird

So, when you point out innumeracy I think you should explain it with patience. Explain it understanding that some people who may be well informed and intelligent in other matters might not understand why, for example, decreasing by more than 100 percent is nonsense.

(100 percent is all of something. A 50 percent decrease is half. '100 percent decrease means' it's zero. Decrease by more than 200 percent? means it's less than zero, negative. Negative prices make no sense. )

So, when you point out innumeracy I think you should explain it with patience. Explain it understanding that some people who may be well informed and intelligent in other matters might not understand why, for example, decreasing by more than 100 percent is nonsense.

(100 percent is all of something. A 50 percent decrease is half. '100 percent decrease means' it's zero. Decrease by more than 200 percent? means it's less than zero, negative. Negative prices make no sense. )

@futurebird I have seen studies that show membership in a group stereotyped as not being good at something actually materially affected a person's performance in said areas. We tend to accept the stereotypes placed on us by society, on average.

@JessTheUnstill

As a teacher I find projecting intelligence on to other people can be very effective.

"You might not have thought about percents for a while, but I'm certain someone like you can see how ... "

Then fully explain it as you would to someone who didn't know how it worked. Invite people to join the "we get it club" instead of just laughing and keeping them out.

@futurebird When I was still teaching maths, there were a few things I liked to do specifically to reel in the students who had ended up internalizing a story that they were bad at maths and that maths was incomprehensible arcane magic only used by people with very special brains.

The first was to try to emphasize how *human* a lot of our conception of maths is. (It helps here that I'm not a mathematical platonist.) Why do we use base 10? Why did the practice of writing mathematical proofs first pop up in ancient India and Greece, even though eg. Babylonians had been using pretty advanced maths for millennia without bothering to prove anything? Why has so much of mathematical history been preoccupied with finding the "essence" of various constructs; is it just a coincidence that that came out of a culture that had a strong essentialist inclination?

The second was closely related to the first: Putting human faces on all these things. Did you know Pythagoras was deathly afraid of beans, and also that he was the leader of a weird cult? Or that Georg Cantor spent his later years trying to convince everyone that William Shakespeare was actually Francis Bacon writing under a cover name? That we have no reliable biographical information about Euclid at all, and that he may not have been a single individual at all? That Emmy Noether kept teaching out of her own apartment after the Nazis excluded her from the university? I've had many students - *especially* the ones less comfortable with numbers and pure maths - tell me that they could use some of all these little things as "handles" to jog their memories.

The third was to pose absurd questions that had non-obvious answers that maths clearly illuminated. Are there two people in Denmark who have exactly the same number of hair follicles on their heads? (There's about 150.000 hair follicles on an average Scandinavian head and about six million people in Denmark, so...). The story of Abraham Wald and the airplane armouring, the Linda Paradox, a Zombie Apocalypse version of the river crossing problem, etc.

Mostly, I tried to show students that maths is not an exclusive club at all. I won't say I succeeded evenly, but I know many of them appreciated it.

@futurebird there are also patterns that make maths not inherently intuitive; if you increase something by 100% you double it, so you might make a reasonable assumption that if you invert that and decrease 100% you'd get back to where you started.

I.e. if an increase by 100% = x2
shouldn't a decrease by 100% = /2?

Wrong, but not *obviously* wrong.

@philbetts @futurebird

I recently saw a science video that said the star Trappist-1 is "1,800 times less bright" than our sun. I don't like this. I guess that would mean that its brightness is 1/1800th that of the sun, but saying it the way they did is confusing.

So, when you point out innumeracy I think you should explain it with patience. Explain it understanding that some people who may be well informed and intelligent in other matters might not understand why, for example, decreasing by more than 100 percent is nonsense.

(100 percent is all of something. A 50 percent decrease is half. '100 percent decrease means' it's zero. Decrease by more than 200 percent? means it's less than zero, negative. Negative prices make no sense. )

@futurebird What do you reckon the percentage of people is who understand that the reverse of going up 30% is not going down 30%

@futurebird What do you reckon the percentage of people is who understand that the reverse of going up 30% is not going down 30%

Mathematics is a language. But innumeracy is also a language and our president is fluent.

It's not just that he exaggerates, lies, and says things that make no sense when talking about numbers "often" no this is something deeper.

He is deeply committed to *never* speaking about any statistic or numerical fact in a way that would suggest that it's important to understand how basic math works, or even that it exists at all.

This isn't just ignorance or laziness, it's one of his core values.

@futurebird He's literally done this billions of times.