History WritersCannotDoMath / Literature

* ''Literature/TheLaundryFiles'' is a complete aversion. Computational theory and related fields are the key component of magic in the setting, and the main character is one of the most talented computational demonologists of his generation (in a job where getting the math wrong can be fatal - or worse). Expect a crash course on Riemannian, Lorentzian and Calabi-Yau manifolds, the difference between P- and NP-complete problems and the mathematical foundations of the Everett-Wheeler cosmology and it's relation to the Copenhagen interpretation of quantum mechanics. Also, the author insinuates that the reason volume four of ''The Art of Computer Programming'' took nearly 30 years to complete is that someone read and edited out all the bits that might bring the Elder Gods back from beyond the stars, but that some of it is still left in chapter 7.9. The math scans beautifully for those who understand it, and for those to whom the math reads as "blurble blurble jargon blurble" the novels are still completely comprehensible.

*** Snape is 32 years old in ''Chamber of Secrets'', but he was a contemporary of Harry's parents at Hogwarts, implying that Harry's parents were quite young when they had him. This is confirmed by James and Lily's headstone which put their birth in 1970 and their death on the 31st of October 1981. They canonically had Harry at 20 and died at 21, it doesn't seem to be a mistake on JKR's part.

*** Snape is 32 years old in ''Chamber of Secrets'', but he was a contemporary of Harry's parents at Hogwarts, implying that Harry's parents were quite young when they had him.

* ''Literature/SixtyEightRooms'':
** In this book, the kids shrink to the same scale as the Thorne rooms--one inch to one foot. When Ruthie comes across a crack on the ledge that measures a half an inch, the story states she finds it too large to walk over on her own. This crack would actually be scaled to six inches to the shrunken Ruthie, an easy obstacle to walk past.
** A minor issue-- the museum was stated to close at 5 pm. Jack and Ruthie slipped into the corridor at 4:55 and got up when Jack looked at his watch to read 6:00. They did not sit for over an hour.

** George R. R. Martin often creates a one-year confusion by using the "in his Xth year" formulation.[[note]]Technically, a person's 17th year is the year they are 16--the year ''leading up to'' their 17th birthday--just as a person's first year of life starts when they are born, not when they turn one--but in current usage it rarely means anything other than that the person is ''now'' 17.[[/note]] For instance, Jaime Lannister is claimed to have been elected to the Kingsguard in his 15th year. However, whenever his age is referred to, the book clearly says 15.

** The most commonly noted example is that Hogwarts appears to be a lot smaller than the narrative suggests. If we assume that Harry's year is representative of a typical Hogwarts class, and that the Sorting Hat scene goes through the entire incoming class (Rowling [[WordOfGod had a notebook listing them]] so she could keep track), there are only about 40 students per year. Multiply that by seven years, and you get fewer than 300 students in total. The narrative implies there are quite a few more students, like a mention of "200 students in green" at a Quidditch match; Rowling said she envisioned Hogwarts as having around 750 students. But we don't see any of them. We only see five boys in Gryffindor in Harry's year, which is more consistent with the smaller number[[note]]assuming the same number of boys as girls, that's 10 students per house, times four houses is 40 students per year[[/note]]. The classes have around 20 students in them, which if the smaller number were true would mean the Houses are sharing classes -- which is exactly what we see. And there's only one teacher per subject with fourteen subjects; if there were really 750 students, either only a third of the school day is spent in class, or the teachers are all using Time Turners to teach three classes at once.
** The same problem applies to the Wizarding World as a whole. Rowling claimed there were around 3,000 witches and wizards in Great Britain. That's ''really'' not a lot. For reference, a town with 3,000 inhabitants wouldn't even be big enough to have its own police station. Wizarding Britain, on the other hand, has enough wizards for a massive government bureaucracy with a ton of departments, an extensive law enforcement body with special forces and intelligence sections, and an entire league full of professional Quidditch teams. And that's before you take into account the 750-odd Hogwarts students, implying that fully a quarter of the magical population is in school. To put it into context, Britain has around 200,000 active lawyers -- and that's just the [[EvilLawyerJoke Dark Arts practitioners]].
** The Quidditch World Cup in ''[[Literature/HarryPotterAndTheGobletOfFire Goblet of Fire]]'' is said to be the 422nd edition of the tournament. And ''Literature/QuidditchThroughTheAges'' says that there are four years between each World Cup -- but also that the first one was in 1473, which is impossible if the one in ''Goblet of Fire'' took place in 1994. You'd have to assume that ''nowadays'' it's every four years, but in the past it had about as erratic an interval as the [[https://en.wikipedia.org/wiki/Copa_América#Results Copa América]]. Which makes sense, considering magic is involved (for instance, the entire 1877 tournament had to be redone because nobody could remember it). Pottermore {{lampshaded}} the whole thing in its article on the Quidditch World Cup, claiming that "[a]s with so much else about the wizarding world's most important sporting competition, many query the accuracy of this statement."
** How is Ollivander making any money selling wands for seven Galleons apiece? Per Rowling's exchange rate, that's around 35 British pounds. But this is for a device that's supposed to last the owner a ''lifetime''. Assuming Ollivander sells 200-odd wands every year, which is generous,[[note]]One would have to assume 100 of those wands are for incoming Hogwarts students -- even though the books imply that Hogwarts incoming classes are much smaller. The other 100 would be for people who've lost or broken their wands. And this is assuming he has a monopoly in the wandmaking business, but the books are clear he does not[[/note]] he'd only make around 7000 pounds a year. If [[SeverelySpecializedStore all he sells are wands]], that's not nearly enough to stay in business. And this is before getting into the fact that he has captive demand -- if "the wand chooses the wizard", he's got a brilliant opportunity to extort young witches and wizards because he's the only one with the product that will allow them to make the most of their magic.
** How much older are Ron's brothers Bill and Charlie? Both had left Hogwarts by the time Harry and Ron start there. Rowling just said Charlie was two years older than Percy, and Bill two years older than Charlie -- except since Percy is in his fifth year in ''Philosopher's Stone'', that means that Charlie should have been in his last year of Hogwarts or very recently graduated. This makes no sense when combined with the comment on Gryffindor's losing streak having lasted since Charlie last captained the team; assuming he played until graduation, that would have to be a couple of years at least. And it's more than that, because ''Prisoner of Azkaban'' says Gryffindor's last Cup win was seven years earlier, implying that he's at least ''seven'' years older than Percy and left the year before Percy started. (Rowling upped the gap between Percy and Charlie to three years, which solves the graduation problem but not the Quidditch problem.) No one disputes when Bill graduated, but it does create an odd line where Ginny mentions wanting to attend Hogwarts since Bill started, which would have been when she was a year old at the earliest.
** Other characters' ages just don't line up. Snape and Lucius Malfoy were said to be in the same social group at Hogwarts, but supplemental material suggests that Lucius is ten years older than Snape, so they couldn't have coincided at Hogwarts. A flashback in ''Deathly Hallows'' reveals Lucius was a prefect in Snape's first year, making him at least five years older. It also states that Snape was 32 years old in ''Chamber of Secrets'', but he was a contemporary of Harry's parents at Hogwarts, implying that Harry's parents were quite young when they had him. Then you read that Bellatrix was ''also'' in Snape's social group at Hogwarts, but her younger sister Andromeda's daughter Tonks is in her twenties throughout the series, implying that Andromeda had her ''real'' young -- like, she had a TeenPregnancy right after graduating from Hogwarts. And trying to fit this into the timeline, that would imply that Bellatrix was probably in her sixth or seventh year when Snape started, so unlikely to be in his social group either.

** Slytherin Quidditch captain Marcus Flint is introduced in ''Philosopher's Stone'' as a sixth-year. But two years later, he's still Quidditch captain when he should have graduated the year before. When faced with this, Rowling replied, "Either I made a mistake or he was held back a year. I think I prefer Flint making the mistake." Later editions of ''Philosopher's Stone'' correct this by calling Flint a fifth-year instead of a sixth-year.

* In Greg Bear's ''Literature/{{Eon}}'', the protagonists find a source of an "inverse-square force". A couple of pages later, the force is described as increasing in strength as one got farther from it.

* ''Literature/Wereling2009:'' In the third book, Ella introduces Trey to the rest of the [=LG78=] werewolf pack; the narration mentions half a dozen members, and from the context, might not be counting Ella. By the end of the book, there are five members total, which includes Ella.

* Faye Kellerman's ''Literature/PeterDecker'' series has been playing a bit loose with Decker's age in order to keep him out of retirement. In the first book, which was published in 1986 and presumably takes place no later than that year, Decker was described as 38-years-old and a Vietnam vet. Rina's two sons are seven and eight. By the 2010 book ''Hangman'', the sons are still in college and Decker is just turning 60. You do the math. [[note]]It is 24 years between 1986 and 2010 which would make Decker 62, close to the age given, the real issue is that the sons would be 31 and 32 respectively, or when factoring in the two year dilation, 29 and 30.[[/note]]

** There's simply no way that Ana can interview Grey on Monday, May 9, 2011 (the date given in E.L. Jame's short story ''Meet Fifty Shades''), have five days pass, meet Grey in the hardware store in which she works on Saturday (which would be May 14), have "several weeks pass"--so three weeks at the very least--have a week of finals and then graduate on May 27. Any way you look at it, you can't squeeze five weeks between May 9 and May 27 without a time machine.

* Although a scientist, Creator/IsaacAsimov clearly didn't do the math when it came to Trantor, the planet covered by one city in the ''Literature/{{Foundation}}'' trilogy (and the inspiration for Coruscant in ''Franchise/StarWars'').

** The original has a bad case of this. The most prominent example is the author appearing to have no idea how long driving from one place to another would take. There is an attempt to justify it by establishing that Edward DrivesLikeCrazy, but even then there are moments that are suspect. The most egregious example would be the claim that Edward and his brothers drove from Forks, Washington to Alaska in 16 hours, which would not only require them to be driving at ludicrous speeds without stopping for gas or anything, is not even possible. The trip from Forks, Washington to Denali Borough in Alaska, is a road distance of over ''2,300 miles'', meaning he drove at an average of 144 miles per hour, also known as 230 kilometers per hour.

* There's a children's book titled ''Brog the Stoop'' in which the race of Stoops are restricted to '''one''' child per family. The author really should have noticed that this would lead them to die out very quickly, each generation being at most half the size of the previous one.

** Other characters' ages just don't line up. Snape and Lucius Malfoy were said to be in the same social group at Hogwarts, but supplemental material suggests that Lucius is ten years older than Snape, so they couldn't have coincided at Hogwarts(A flashback in ''Deathly Hallows'' reveals Lucius was a prefect in Snape's first year, making him at least five years older) It also states that Snape was 32 years old in ''Chamber of Secrets'', but he was a contemporary of Harry's parents at Hogwarts, implying that Harry's parents were quite young when they had him. Then you read that Bellatrix was ''also'' in Snape's social group at Hogwarts, but her younger sister Andromeda's daughter Tonks is in her twenties throughout the series, implying that Andromeda had her ''real'' young -- like, she had a TeenPregnancy right after graduating from Hogwarts. And trying to fit this into the timeline, that would imply that Bellatrix was probably in her sixth or seventh year when Snape started, so unlikely to be in his social group either.

** As this [[https://acoup.blog/2019/05/28/new-acquisitions-not-how-it-was-game-of-thrones-and-the-middle-ages-part-i/ blog]] points out the number of tens of thousands he gives for the armies are often implausible with the medieval logistics available. Dropping a zero from the total gives much more beliveable

** There's a big plot hole in ''Literature/TheThrawnTrilogy'' where Darth Vader was involved in a plot-critical event 44 years before the present day of the story. Luke and Leia, at this stage, cannot be any older than 28, meaning Anakin Skywalker would have had to have been Darth Vader ''sixteen years'' before his children were born. While this preceded the release of the prequel trilogy which obsoleted a lot of what Creator/TimothyZahn had based his writing on (particularly the nature of the Clone Wars and the fall of the Old Republic), he apparently just didn't consider the ramifications of the plot point on the family timeline (never mind that this meant Vader would presumably have had to have been a Dark Jedi for at least 16 years ''before'' being crippled and turned into a cyborg).

** Other characters' ages just don't line up. Snape and Lucius Malfoy were said to be in the same social group at Hogwarts, but supplemental material suggests that Lucius is ten years older than Snape, so they couldn't have coincided at Hogwarts. It also states that Snape was 32 years old in ''Chamber of Secrets'', but he was a contemporary of Harry's parents at Hogwarts, implying that Harry's parents were quite young when they had him. Then you read that Bellatrix was ''also'' in Snape's social group at Hogwarts, but her younger sister Andromeda's daughter Tonks is in her twenties throughout the series, implying that Andromeda had her ''real'' young -- like, she had a TeenPregnancy right after graduating from Hogwarts. And trying to fit this into the timeline, that would imply that Bellatrix was probably in her sixth or seventh year when Snape started, so unlikely to be in his social group either.

* There's a glaring example in the ''Literature/WeatherWarden'' book series by Rachel Caine. The lead character, Joanne, has a supernatural adult daughter named Imara, who technically doesn't age. In the fifth book, ''Firestorm'', a character comments to Joanne that she is "plenty old enough" to have an adult daughter. Joanne's character is ''twenty-eight'' years old, there's no way she could have an adult daughter. Suppose Imara is twenty years old; that would mean Jo had her at eight years old. Granted, girls as young as five giving birth have been documented, but the clear implication of the above statement is that Jo is old enough to have had a child at a typical age long enough ago that that child would be an adult.

* ''Literature/{{Twilight}}'':

** In ''Breaking Dawn'', Carlisle states that Renesmee's growth seems to be slowing down after she is born. This is a child that spend a month in the womb, thus gestating at nine to ten times the rate of a human baby; then, three to four months after she is born, she apparently looks about five. That means that after she was born, she grew at fifteen to twenty times the rate of a human child.

** The Quidditch World Cup in ''[[Literature/HarryPotterAndTheGobletOfFire Goblet of Fire]]'' is said to be the 422nd edition of the tournament. And ''Literature/QuidditchThroughTheAges'' says that there are four years between each World Cup -- but also that the first one was in 1473, which is impossible if the one in ''Goblet of Fire'' took place in 1994. You'd have to assume that ''nowadays'' it's every four years, but in the past it had about as erratic an interval as the [[http://en.wikipedia.org/wiki/Copa_América#Results Copa America]]. Which makes sense, considering magic is involved (for instance, the entire 1877 tournament had to be redone because nobody could remember it). Pottermore {{lampshaded}} the whole thing in its article on the Quidditch World Cup, claiming that "[a]s with so much else about the wizarding world's most important sporting competition, many query the accuracy of this statement."

** Slytherin Quidditch captain Marcus Flint is introduced in ''Philosopher's Stone'' as a sixth-year. But three years later, he's still Quidditch captain when he should have graduated the year before. When faced with this, Rowling replied, "Either I made a mistake or he was held back a year. I think I prefer Flint making the mistake." Later editions of ''Philosopher's Stone'' correct this by calling Flint a fifth-year instead of a sixth-year.

* ''Threshold'' by Caitlín R. Kiernan contains a rare attempt of an author to include mathematics higher than arithmetic, but unfortunately falls headlong into this trope. The book lists a regular heptagon (a seven-sided polygon with all sides and angles the same) as an {{Alien Geometr|ies}}y based on the fact that a regular heptagon is not constructible. However, in geometry, "not constructible" means "cannot be drawn with only a straightedge and compass." It does not mean "cannot be made with any tool known to man" (you can [[https://en.wikipedia.org/wiki/Heptagon draw a regular heptagon]] just fine if you have an accurate protractor and ruler) and most definitely doesn't mean "cannot exist in nature" or "seeing one will cause you to GoMadFromTheRevelation."

* In ''The Poisoned Chocolates Case'' by Anthony Berkeley, a character enumerates twelve conditions the criminal must fulfill, and states: "The mathematical odds against their all being fulfilled in one person are... 479,001,600 to 1. And that, mark you, is if all the chances are even ones." Two errors here. Firstly, 479,001,600 is 12 factorial, but he should be calculating two to the twelfth power -- 4,096. Secondly, those are the odds against ''any particular'' person fulfilling all the conditions, which is completely irrelevant -- after all, assuming he's correct in saying that the crime must have been committed by someone fulfilling all twelve conditions, the probability that ''someone'' fulfills all the conditions is 100%! The question should be, "What are the chances that, given that a particular person fulfills all the conditions, that person is the criminal?" -- and the answers to the two questions will not, in general, be the same. This particular fallacy is common with real-world prosecutors too. "The chance that the defendant's DNA would match that found on the crime scene by pure chance is less than one to a million" sounds much more convincing than "The defendant is one of ten or twenty people in the New York metro area whose DNA match".

* The narrator of Creator/FrederikPohl's ''Day Million'' is aware that his listeners are from around "the six or seven hundred thousandth day since Christ." He then identifies Day Million as "ten thousand years from now." Even assuming that his earliest estimate is correct (which would be well before the story's 1966 publication), that makes only forty days to a year. Granted, it could be just the impatient LemonyNarrator's carelessness, but you would think at least that fellow author and praising commentator Creator/RobertSilverberg would have something to say about it.

* If you look at the family tree in the last chapter of ''Centennial'', you'll notice that Prudence Wolf (1866-1936) was the mother of Pale Star Zendt (1874-1939).

* In ''Literature/LeMorteDarthur'', [[Myth/KingArthur Lancelot]] faces a dozen armored knights while unarmored himself. He kills one of them, takes his armor, then kills "the remaining twelve." Malory takes the trouble to name each one individually, so you'd think he'd have remembered to decrement the count.

* ''Literature/LittleWomen'' apparently starts on Christmas Eve of 1860, because a year later, when Amy makes her will, she writes the year "1861" on it. Yet the Civil War is portrayed as well underway from the start, when it began in 1861. Then, toward the end of the book, Jo reflects that she's now almost 25 years old, but a close look at the timeline reveals that she should only be 23.

* In Creator/LouisSachar's ''Literature/WaysideSchool'' series, Wayside School has thirty classrooms, but the total number of students is given as ''4500''. That would be an average of 150 students per classroom, and since we know that the 30th classroom has 29 students...

* ''Literature/WiedergeburtLegendOfTheReincarnatedWarrior'' volume 8 states that only two thousand people survived [[spoiler:the Sekbeist attack on Vesperia]], said to be less than "a thousandth of a percent" of the previous population of 550,000. Actually, that's ''four'' thousandths of a percent.