The number of times I’ve had to explain to people that having something decrease by 50% and then increase by 50% still results in a decrease (and still not had people understand) makes this entirely unsurprising.
this post was submitted on 19 Dec 2025
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Chapotraphouse
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The average American reads at below a 6th grade level. I don't know the average level of math skills. About second grade?
if i was reading at a college level in the 6th grade does that mean I'm like 20 grades higher than the average american???
If you ever visit Texas you better not show off yer book learnin' because it might even be a capital offense.
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I'll have to read even less to make up for this, smh my head
I consider myself "bad at math" and even I understand that. Wtf is happening??
But if it goes down by 50 and then up by 50 it's still the same, even in ~~evil commie foreign~~ "%" ~~dollars~~.
Strike the evil commie parts and I have heard this word for word. 
“If you’re talking about 50% of the original value in both cases, yes, but not when you’re talking about a decrease followed by an increase”
And I’ve solidly lost them.
Percentages are multiplicative, not addative, so if you go down 50 and then up 50 (or vice versa) you end up at 75% of the original value.
Equation would be original value * (1 + % ÷ 100)
So if we start with 1, 1 * (1-50/100) = .5 .5 * (1+50/100) =.75
In simplified fractions, 1 * 1/2 * 3/2= 3/4
I know. Far too many people I’ve had exactly this conversation with don’t seem to be able to grasp that, though, no matter how I present it to them.
how do people not get 1*.5 = 0.5 and then 0.5*1.5= 0.75 YOU JUST SHOW THEM THE NUMBERS
I usually use 100 instead of 1 so that the only decimals are the percentages 
yeah but my thinking is if you're explaining to people who don't think so good then it's like, okay, you have one of a thing, you make half of that. Then, you make half again more than that, and, see, half of a half is only a quarter, so, you only have three quarters once you add it all together
then i bang some rocks together to establish dominance
idk i'm drunk but also so many people smoke weed they'd probably get it
Yep that's how I'd explain it too, maybe with a cup of water so they can see it doesn't get back to the same level when adding 50% of the remaining 50%
do it with a pizza (because burgers are more difficult to slice)
imagine a pizza, then slice etcetc
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But if it goes down by 50 and then up by 50 it's still the same, even in evil commie foreign "%" dollars.
Wouldn't surprise me if % were invented to scam people. Why wouldn't you just use decimals or fractions for everything.
There I also no non-scam reason why we suddenly use +/- when it comes to percents rather than multiplication. There is also multiple ways how multiple percentages are combined in practice, it's not consistent.
Percents are decimals…. You just multiply them not add them and people are stupid.
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This would pass as weed scene dialogue
Dude, pass the bong. You blew my mind but I need to go further.
Americans: more innumerate or more illiterate? the answer may surprise you
Remember when 56% of people surveyed were in favor of banning Arabic numerals?
They kinda did
As with Woolverton's screenplay, several characters and plot elements were based on The Thief of Bagdad,[33][34] although the location of the film was changed from Baghdad to the fictional Arabian city of Agrabah due to the Gulf War.[35] Because the war prevented them from travelling to Baghdad for research, most of their research took place at the Saudi Arabian expo at the Los Angeles Convention Center.[36]
the kids by and large can't reason about numbers for shit. i've even encountered one that essentially had a better grasp of algebra than fractions.
source: working with the kids
one that essentially had a better grasp of algebra than fractions
He's a potential professional mathematician!
Partially relevant: I watched this video the other day about some guy who was quoted 0.002c per kb for Verizon roaming data charges, but was charged $0.002 per kb. He goes through multiple excruciating customer service rep calls repeating the same basic point that they got the units wrong in the calculations, and none of them understand the error, including the refund team. Essentially they see 'figure after the decimal point' means we are now dealing with 'cents', not .002 of a dollar, so they repeat that he was being charged 0.002c despite the contrary.
Long way to say, I am not shocked in the slightest by 'fuzzy maths' being used for percentage reductions
I feel stupid because I don't get it. What else would .002 of a dollar be? Is the dollar weird and cents don't correspond to that?
I'll share the vid, it's quite long. Apparently this all went down seven years ago but I only watched the video recently
https://www.youtube.com/watch?v=nUpZg-Ua5ao
Essentially:
Man calls up Verizon and asks what the roaming rate is.
Verizon rep tells him verbally it is "zero point zero zero two cents" per kb
He confirms it's "zero point zero zero two cents" per kb and asks them to note that on his account
Verizon rep writes it down on the account as $0.002 (i.e. zero point zero zero two dollars).
He is charged for his usage, which comes out to something like $75.35 for his usage, which is one hundred times more than he expects.
He calls up Verizon and asks them to explain. He confirms that the quoted rate was 0.002c
They say yes, it is zero point zero zero two cents, while they are looking at a written rate of $0.002.
He then spends hours trying to explain to multiple reps that just because the value is after the decimal point, it doesn't make the units into cents overall, you still have to look at the quoted unit, which was written down as $0.002 i.e. dollars
The reps do not understand the difference. They repeatedly multiply his kb total by $0.002, while saying that it's 'zero point zero zero two cents' and arriving at the $73.35 total and telling him that it's the correct amount.
If it sounds like it should be simple, yes, it is as simple an error as you think and yes the reps repeatedly fail to understand $0.002 isn't the same as 0.002c. it isn't that they misread 0.002c as 0.2c, their system units were always in $, and they for whatever reason think that $0.002 is 'zero point zero zero two cents'
He is eventually given 50% off his bill after it goes up the chain He complains again, then his bill is waived.
Oooooh I didn't get the 0.002c like .002% of a cent! Thank you!
Well technically...
If you put a % sign on it you are changing it again. 0.002c is 0.2% of a cent. 1% of a cent is 1/100th (or 0.01) of a cent. So 0.002% of a cent is 0.00002 cents. Since 1 cent is 1% of 1 dollar though, 0.002c is equal to 0.002% of a dollar.
It seems like this could have all been avoided if he had said “I was quoted two-thousandths of a cent per kb, but was charged two-tenths of a cent per kb, and thus need to be made whole” but what do I know?
It took him a long time to get to what the issue was, that he only starts to think about how to explain the error well-into the repeated calls. It's like he thought the issue was so self-evident that he doesn't start to refine and break down his explanations of why it's wrong until too late. Keeping things within one unit (rather than swapping between $/¢) as you suggest may have been better, but after two hours on the phone he sounds like he's already at his wit's end. It's really frustrating, so if you do have the time it's worth listening to
"I was charged $2/Mb when I was quoted 2¢/Mb"
He is eventually given 50% off his bill after it goes up the chain He complains again
I would be complaining about chest pains at that point
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0.002¢ == $0.00002
It's easier if you replace the units with meters/centimeters:
Is 0.002m == 0.002cm ?
“But this one goes to 11…”
TDS confirmed.
THE NUMBERS DONT LIE, AND THEY SPELL DISASTER AT SACRIFICE
if economy bad when number high just set number really low? or vice versa? save us economy boy
Is this one of those arguments they make so you get so caught up on the premise and not the underlying issue?
I think this more of an emperor's new clothes shtick to cover for his boss that relies on widespread innumeracy rather than Lutnick genuinely not understanding percentages. Still infuriating, though.
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