->''"[[IncrediblyLamePun (It's 2)]] [[PrepareToDie DIE!]]"''
-->-- '''Sho Minamimoto''', ''VideoGame/TheWorldEndsWithYou''

ExactlyWhatItSaysOnTheTin, more or less. It could be a {{Mook}}, The TagalongKid, [[SixthRanger The New Guy]], or [[BookDumb The Idiot of the Group]], but on a [[MillionToOneChance random lark]], you show them your math homework/accounting/hyper-dimensional missile schematics. Within seconds, they know what's going on, where the problem is, what to do to fix that, and then proceeds to spell it out, astonishing the entire group. When prompted, they generally explain they [[YouDidntAsk grew up on a math farm or something of the like]] or just simply, "I'm good with numbers." Can be anything from rapidfire simple math, to supplementing baseball with trig projections, [[AwesomenessByAnalysis but then you're just awesome that way.]] Is generally a ChekhovsGun for a plotpoint later in the episode, or can evolve into a RunningGag for the series and short hand for doing mathstuff really fast. Rather logically, the RobotBuddy and TheSpock often have this ability. It's also a common ability of the IdiotSavant.

Definitely TruthInTelevision, as quite a few people in RealLife have this ability. Most of them are mathematicians, but not all of them. In fact, there are even competitions for mental math.

May sometimes speak with a MouthfulOfPi. See also MadMathematician. May result from SuperIntelligence.
----
!!Examples

[[foldercontrol]]

[[folder:Anime & Manga]]
* Pinoko from ''Manga/BlackJack'', who memorized her guardian's credit card number so she could follow him anywhere he went.
* Rokuro from ''DeadmanWonderland''. ''Woo'', he even calls himself the human calculator.
* Sadaharu Inui, the Seigaku GeniusBruiser from ''Manga/ThePrinceOfTennis''. This makes him victim of {{Flanderization}} in both {{fanon}} and canon.
* Despite his general [[BookDumb doofiness]], ''Anime/YakitateJapan'''s Azuma Kazuma turns out to be nothing short of a mathematical genius when he ''solves a cryptographic problem in base 26'' in less than a minute.
* ''LightNovel/ACertainMagicalIndex''
** It's not made a big deal of or even really mentioned outright (in the anime, anyway), but Accelerator is GoodWithNumbers as one of the [[RequiredSecondaryPowers necessary abilities]] to actually use his esper ability properly. The [[GoodIsDumb nerf]] he gets is actually based on brain damage that affects his mathematics ability and requires a ''ten thousand person'' ''HiveMind'' to correct for a mere 15 minutes at a time. ItGetsBetter, as [=GROUP's=] enhancements are able to extend his Esper Mode to 30 minutes, then ''he himself'' manages to reduce his battery consumption by ''90 percent'' so he can use it for undertaking longer missions.
** It's been implied that the more powerful an Esper is, the more likely that he is GoodWithNumbers. [[ImaginationBasedSuperpower Dark Matter]], [[WaveMotionGun Rail]][[ShockAndAwe gun]], and [[EnergyWeapon Melt]][[FrickinLaserBeams downer]] are all very powerful espers with immense Physics (and, you guessed it, Math) knowledge. [[TeleportersAndTransporters Teleporters]] (except [[BackStab Kill Point]]) can calculate ''[[UpToEleven up to the eleventh dimension]]''.
** Index herself, due to her incredible memory, is also a hot hand at numbers.
* This is Kenji's defining ability in ''Anime/SummerWars''. He's so damn good he solves 2056-bit encryption in his head.
* ''Anime/MagicalGirlLyricalNanohaAs''
** [[ComicBookAdaptation The supplementary manga]] revealed that, [[AlwaysSomeoneBetter much to the competitive Alisa's chagrin]], both Nanoha and Fate are like this. Fate especially, to the point where Nanoha's sister goes to her for help on her high school math homework even though Fate's in elementary school. The same chapter also mentioned that the magic in the series requires a good bit of math, so being good with numbers is one of the reasons why they're both top mages.
** There's also [[PersonOfMassDestruction Hayate]], who is the only known member of the TSAB with a [[RankInflation SS]] ranking. Since she didn't develop her powers like everyone else she's not as good with spell control and multitasking, and has to have [[HomeBase Long Arch]] or Reinforce aim for her.
* Inverted in ''Manga/{{Nichijou}}''. Nano, a [[RidiculouslyHumanRobot robot girl]] who [[IJustWantToBeNormal wishes she wasn't]], apparently has trouble solving "3260 plus 260, divided by 320," even going so far as to pull out an abacus to work out the problem.
* In ''Anime/CodeGeass'', several of [[MagnificentBastard Lelouch's]] HumongousMecha require his superior mathematical skills, including his Shinkiro's absolute defense shield and [[spoiler:the anti-FLEIJA device which required incredibly complex calculations to be input within 19 seconds of use.]]
* [[Anime/{{K}} Fushimi Saruhiko]] is revealed to be this in the interview with Misaki on the Drama CD. He manages to solve an equation Misaki came up with (just spouting numbers, basically) in a split second.
--> '''Misaki''': Alright. Here we go~ Question: What is 37 + 21 - 44 x 17 / 4?
--> '''Saruhiko''': 59.5
--> '''Misaki''': ...Eh?
--> '''Saruhiko''': 59.5. But if you calculate it in proper order [[note]]multiplication and division first, then addition and subtraction[[/note]] it would be -129.
* Cocoa of ''Manga/GochuumonWaUsagiDesuKa'' may be very spacey, but she is something of a mathematics savant, able to calculate large sums instantly and can count prime numbers up to the thousands.
[[/folder]]

[[folder:Comic Books]]
* TeenGenius Amadeus Cho from ''ComicBook/TheIncredibleHercules'' can do advanced physics in his head, complete with glowing diagrams around him. He's claimed to be good enough that he can use math to stop a charging rhino with a grape seed, and proved it when he fought [[Comicbook/IncredibleHulk the freaking Hulk]].
* ''SupermanRedSon'' establishes that Lex Luthor is a super-genius scientist at STAR Labs. This isn't really surprising, but this trope comes in when he casually hands his OSS handler a formula to balance the economy. However, he says it's just the principles, and the Treasury will have to do the number-crunching for the specifics.
[[/folder]]

[[folder:Films -- Live-Action]]
* In ''Film/TheDarkKnight'', Lau explicitly states that he is "good with calculation" while attempting to betray the whole Gotham mafia. He intends to leave with the money they entrusted him with. Had it not been for Batman and his brutal ways, he would have been able to actually make it. Though it is quite possible that the Joker himself had been planning it all since the very beginning -- he ''is'' quite the CrazyPrepared guy.
* Kazan, the autistic savant in the movie ''Film/{{Cube}}''.
* Wynn from the prequel ''Film/CubeZero''. [[spoiler:Depending on how you interpret the ending, he may be the same person as Kazan.]]
* Ben Campbell from the movie ''Film/TwentyOne'', but that's to be expected when he counts cards as a part time job. His EstablishingCharacterMoment is him verbally tallying up a complicated order for a customer at a clothing store, including knocking off part of the price by applying his own employee discount towards the order, all without aid of a pen and paper or calculator. In the trailer, [[FunWithSubtitles the math is written out on screen for the benefit of the audience]], though that bit was left out in the movie itself.
* John Nash of both real life and the biographic film ''Film/ABeautifulMind''. He manipulates glasses of water to alter the optic lines refracting through them to match a tie on the other side, solves complex cryptograms based on the Sierpinski Gasket in his head and revolutionizes all economic theory since Adam Smith. [[RoomFullOfCrazy He's also crazy as a loon.]]
* At the end of the third AlternateUniverse live-action ''Manga/DeathNote'' movie, [[spoiler:L adopts a Thai kid who's good with math. It's heavily suggested the kid grows up to be Near.]]
* Harold Crick in ''Film/StrangerThanFiction''. A routine occurrence in his life is being given math equations by his coworkers, which he solves in his head instantly.
* ''Film/GoodWillHunting''. Will's genius is "discovered" while he's working as a janitor at MIT. In just a few minutes, he solves an impossibly complex combinatorics problem that was left on the chalkboard after everyone went home. Prof. Lambeau had given his students the entire ''semester'' to work it out.
[[/folder]]

[[folder:Literature]]
* Andrew Jackson "Slipstick" Libby from Creator/RobertAHeinlein's ''Future History'' series. In his introductory short story ''Literature/{{Misfit}}'', he replaces a spaceship navigation computer by performing all spatial calculations needed to navigate the ship in real time ''in his head''. And his mathematical genius comes to light when he warns of a critical calculation error made in setting a small nuclear charge based on what he's learned about laying the charges just by watching the officer making the calculations. (For the younger generation who've never seen one, a "slipstick" is a nickname for a [[https://en.wikipedia.org/wiki/Slide_rule slide rule]], a type of analog calculation aid common before hand-held calculators got good enough to do things like logarithms.)
* Also from Heinlein, Deety Carter from ''Literature/TheNumberOfTheBeast'' is as fast a calculator as Slipstick Libby. She also has a photographic memory and an incredibly precise circadian rhythm -- i.e., a clock in her head. She's a slight subversion, though, in that she says that her lightning calculator ability is pointless with computers around (except that she can see a glitch in a program much more easily than most people).
* Romeo "Mo'Steel" Gonzalez from ''{{Remnants}}'', able to tell how many years and days he had been in stasis with just a glance at a counter showing how many minutes had passed. It totaled "five-hundred years, twelve days, and some spare change."
* Meg Murry, from ''Literature/AWrinkleInTime'' and other books by MadeleineLEngle.
* ''[[ComicBook/XWingSeries Wraith Squadron]]'''s Voort "Piggy" saBinring is an [[PlayingWithSyringes enhanced]] [[PigMan Gammorrean]], and a math genius. During dogfights, while flying and fighting on his own, Piggy is capable of keeping track of his squadronmates and the enemy, and frequently chimes in with suggestions such as "[[YouAreNumberSix Three]], recommend you break left ''now''" and "Nine, recommend you fire ''now''." At the end of ''Solo Command'', his realization about the true nature of an elite enemy squadron helps save the day.
* Otto Malpense from ''[[HIVESeries h.i.v.e.]]'' is the archtype of this trope; he figures out the equation that a computer is using to generate a bunch of moving lasers ''in his head'', closes his eyes, and does the equivalent of walking in between raindrops, without getting hit. Justified, seeing as he's [[spoiler:a geneticially-altered clone designed to have a brain with roughly the same processing power as a uber-intelligent AI, able to think both like a human and like a machine, and interact remotely with complicated computer systems and brush aside their security networks.]]
* In Scott Westerfeld's ''Literature/{{Midnighters}}'' trilogy, one of the special abilities you can have if you were born at midnight (and probably the most useful) is the ability to do lengthy, complex mathematical calculations easily in your head.
* Mark [=McHenry=] from ''Literature/StarTrekNewFrontier'' is specifically good with warp calculations, headings, speeds, and anything else related to navigation and piloting, much like the ''Franchise/StarTrek'' examples below. In fact, at one point, a character specifically compares him to Data, in the "OK, the last time someone was this good, he was an android; what's up with this one?" sense. We eventually learn that [[spoiler:Mark is a descendent of Apollo (from the original series), and linked at some basic level to the universe at large.]]
* ''Literature/{{Discworld}}''
** The Bursar of Unseen University is this. Years ago, he was "a man whose idea of an exciting time had once been a boiled egg", and he has been driven totally, completely insane over the course of several books by Archchancellor Ridcully's habit of shouting at him and generally being as [[LargeHam Hammy]] as possible. However, if you ask the Bursar a question that has anything to do with math (as his title suggests) he is able to answer it no matter which reality curve his mind is riding at the time. Since it's difficult to tell if he's really all right after things like nasty shocks, in later books this becomes a way of diagnosing him; if he can still answer a math question correctly and immediately, he's perfectly fine. Ridcully even seems to know this:
-->'''Chair of Indefinite Studies:''' I don't see why. Just because he can do things with numbers doesn't mean everything else is fine.\\
'''Ridcully:''' Doesn't need to be. Numbers is what he has to do. The poor chap might be slightly yo-yo, but I've been reading about it. He's one of these idiot servants.\\
'''Dean:''' Savants. The word is savants, Ridcully.\\
'''Ridcully:''' Whatever. Those chaps who can tell you what day of the week the first of Grune was a hundred years ago --\\
'''Bursar:''' -- Tuesday --\\
'''Ridcully''': -- but can't tie their boot laces.
** By ''Unseen Academicals'', however, he has either lost several more of his faculties or just been [[RetCon retconned]] into an incompetent -- Unseen University's finances are in a mess and Ponder Stibbons has had to take on the Bursar's job (in addition to his twelve ''official'' positions, and probably just about everything else that needs to get done, ever) because he "regards the decimal point as a nuisance". An AlternateCharacterInterpretation of this is that after discovering imaginary numbers and ''n''-dimensional manifolds in ''Discworld/TheScienceOfDiscworld'', he refuses to descend from higher maths back to boring old arithmetic, and is trying to do the accounts with aleph-null and "umpt".
** Granny Weatherwax is described in ''Maskerade'' as "grudgingly literate, but keenly numerate". It takes her seconds to deduce how much Nanny Ogg is being screwed by the publisher of her cookbook, even taking into consideration things like the cost of materials and distribution. She is also able to figure out the finances of the opera house, which were expertly tampered with and deliberately obfuscated to hide an embezzlement scam.
** ''Discworld/{{Pyramids}}'' introduces the greatest mathematician on the Disc... "You Bastard", a camel. Apparently, ''Discworld'' camels are secretly alarmingly intelligent and spend most of their time doing extremely complex equations in their heads. Although if they are bothered enough by some puny human, they can revert to good old trajectory calculation for a wad of spit in a heartbeat.
** Mr. Bent in ''Discworld/MakingMoney'' is exceedingly good with numbers, so much so that it's a momentous bank-closing event when he makes a mistake. He also finds the imprecision of the Bank clocks "offensive" and fixes them several times a day. By the end of the book we find out that he was raised by a caravan of traveling accountants after running from the circus.
* Talen from ''TheElenium'' is of the "can do normal math ''really'' fast" variety, which he claims developed from practice, and the need for a thief to do on-the-spot appraisals and fence stolen goods. His skill instead comes into play during the Church election's political maneuvering and vote tallying.
* The ''atevi'' from Creator/CJCherryh's ''Literature/{{Foreigner}}'' series. Forming grammatically correct sentences in their language requires mentally doing simple algebra, and they all have the ability to instantly and accurately count things. Further, their cultures have developed a number of extremely complex systems of numerology, which the majority of atevi treat as SeriousBusiness.
* Opal from ''TheVampireFiles'' used to earn extra tips as a waitress by solving math problems in her head as a bar trick. When she did this for a mob boss, he hired her on the spot as a bookkeeper: a job at which she excelled so well that she figured out how much he'd been skimming off the top, based on indirect evidence in his gang's finances.
* Keladry, the protagonist of ''Literature/ProtectorOfTheSmall'', is very good at math. During her page years it's her best subject, and it allows her to assist in engineering projects when she becomes a knight commanding a fort.
* Thursday's daughter Tuesday in the {{Thursday Next}} books is possibly the greatest mathematical genius of all time. She proved there are seven more even numbers than odd ones, and her boyfriend Gavin discovered a three digit ''even'' prime number. Not bad going for a sixteen year old.
* The title character of ''Literature/HoratioHornblower'' does math effortlessly and finds it hard to understand how other people have difficulty. This makes him very good at navigation and whist.
* The mice from ''Literature/TheUnderlandChronicles'', judging by their ThemeNaming, and [[ChekhovsGunman Lizzie]] in ''Gregor and The Code of Claw''.
[[/folder]]

[[folder:Live-Action TV]]
* Lulu from ''Series/TrueJacksonVP''. In one episode, she's hired to be an assistant. When she finishes all the work, another co-worker asks her to solve a math problem on the chalkboard. After a while, she figures out the board was upside down and turns it the right way and solves it.
* River Tam from ''Series/{{Firefly}}'':
-->'''Kaylee:''' She just did the math.\\
'''Zoe:''' You understand how that sounds?\\
'''Jayne:''' What? She killed them with math. What else could it have been?
* Face, on ''Series/TheATeam'', is brilliant with numbers. Naturally he's in charge of the team's finances, which he keeps record of in a little black book (not that he needs it -- he's really good at mental math).
* Malcolm from ''Series/MalcolmInTheMiddle'' can do mental math with ''Credit Cards Numbers''. At one point he helped his dad win at poker by being able to calculate the exact probabilities of the availability of certain cards.
* ''Series/DoctorWho''
** In the serial "The Invasion", Zoe calculates the trajectories to destroy the Cybermen's entire invasion fleet with a handful of missiles. In her head. In thirty seconds. It works a treat.
** [[TheScrappy Adric]] is the proud possessor of a badge for mathematical excellence, and has demonstrated proficiency at the reality-warping mathematics that is Block Transfer Computation.
** The Doctor himself is often described as a genius and occasionally demonstrates. In the [[Franchise/DoctorWhoExpandedUniverse Expanded Universe]] novel ''Interference'', the Doctor briefly transports himself out of a cell using pure mathematics (presumably the same Block Transfer Computation that Adric used).
** In the revival (and as a more HiddenDepths example), Donna Noble puts the number skills she requires as an office temp to work in the episode "The Doctor's Daughter".
** In the episode "42" the Doctor effortlessly solves a mathematical riddle by recognising a series of Happy Primes.
--->'''The Doctor:''' Honestly, don't they teach recreational mathematics anymore.
** In "The Impossible Planet" the Doctor works out the gravitational mathematics of a gravity cone extending from a black hole with a pocket calculator in a matter of minutes.
--->'''Captain:''' It took us two years to work that out!
--->'''The Doctor:''' (Shrugs) I'm very good.
* Sayid establishes his "good with numbers" cred in the pilot of ''Series/{{Lost}}'' by figuring out that 17,294,535 iterations of a 30-second message would take 16 years, 5 months. It takes him about one cycle of the message to calculate this.
* Professor Charlie Eppes from ''Series/{{Numb3rs}}'', who [[InterdisciplinarySleuth uses his skills to solve homicides]].
* On ''Series/{{Friends}}'' Chandler is irked whenever people concede that "numbers" is about all he has going for him. "Math? You're giving me math?"
* On ''Series/StarTrekDeepSpaceNine'', [[spoiler:Dr. Bashir]] starts displaying this characteristic after it's revealed that [[spoiler:he's genetically engineered and therefore has (among other benefits) a superior brain]].
-->'''O'Brien:''' The core matrix is fried. We don't have warp drive.\\
'''Garak:''' Forgive my ignorance, but if we don't have warp drive, how long is it going to take us to reach the closest Federation starbase?\\
'''O'Brien:''' A long time, Mr. Garak.\\
'''Garak:''' How long?\\
[[spoiler:'''Bashir:''']] Seventeen years, two months and three days, give or take an hour.
* ''Series/StarTrekTheNextGeneration'': Likewise, [[RobotBuddy Data]] is pretty good at math.
* Lisa from ''Series/NewsRadio'' often does large calculations in her head. People tend to ask her large multiplication questions whenever they can fit it into a conversation.
* James May on ''Series/TopGear'', at least by comparison to his somewhat BookDumb co-presenters.
* Eli Wallace from ''Series/StargateUniverse'' is a math prodigy. He is recruited into the Stargate program after solving a mathematical proof [[AscendedFanboy embedded in a video game]]. His math skills periodically come in handy, such as in "Light" when he quickly works out an intercept course for the shuttle.
-->'''Rush:''' Whoa-whoa-whoa. Eli, there's many variables here. Are you sure about this?\\
'''Eli:''' ''Math'' boy.
** Put it this way: Rush is an InsufferableGenius of the highest caliber, who can barely tolerate working with others because they can't keep up with his thought processes. ''He'' admits that Eli is smarter than him in some respects, and if he ever admits he needs help with something, Eli's the guy he goes to for it.
* Near the end of ''Series/ThePrisoner'', Number Six mentions being good with figures, though it's not prominently demonstrated -- it's probably more for ironic contrast with his resistance to [[YouAreNumberSix being numbered]].
* The pilot episode of ''Series/WhiteCollar'' demonstrates Caffrey's amazing mathematics. He calculates 64 years of compound interest in a few seconds, then follows that up with the [[SarcasmMode much more difficult]] task of dividing 600 by 4.
* Matt, Shirley's LoveInterest in ''Series/TheAdventuresOfShirleyHolmes''. He even goes to a school for genius kids, and helps [[EverybodyHatesMathematics Bo]] with the answers in a math-based Game Show so he'll be able to get in as well.
-->'''Bo:''' Some geniuses! They can't even count.\\
'''Matt:''' They're [[MouthfulOfPi calculating pi]].\\
'''Bo:''' Oh.
* Fred Burkle from ''Series/{{Angel}}'' is a math genius, and often uses the skill to help the team. Her math skill is so great that, in one episode, a group of demons attempts to cut off her head and steal her brain after she solves a puzzle for them.
* Adam Savage of the ''Series/MythBusters'' has been shown occasionally counting how many frames of high-speed camera footage an object takes to cross a given distance (typically a foot), then doing a series of rapid-fire mental calculations in order to find out its speed in miles per hour.
** In earlier seasons, he'd give the chance of something happening in percentages. Every time, he got it to add up to 100%. (Even ''Jamie'' managed to fall victim to TooManyHalves at least once.) After the fact, he did occasionally forget the actual ratios he'd used, though.
* Olivia Dunham on ''Series/{{Fringe}}'' is shown to have an eidetic memory for numbers and patterns, but it apparently doesn't grant her any greater ability to perform calculations.
* In ''Series/SpartacusBloodAndSand'', the gladiator Ashur uses this talent to gamble, and when he becomes crippled, his master allows him to be his accountant.
* In ''Series/{{Kaamelott}}'', Perceval is an IdiotSavant. He is utterly clueless about map-reading and cardinal points, can't go in a forest without getting lost, don't understand a thing about dates and fail even the most basic logic... Yet he is a goddamn genius with numbers and mathematics; he can do mental calculations lightning-fast, understands games with impossibly complicated rules, and is apparently unbeatable at the shell game....
* ''NashBridges'' had Barry Chen in "Wild Card." He was played by Tommy Chong, but as Nash points out about Barry, the Comptroller for the Chinese Triads in San Francisco, that if he gets involved with anything with numbers, he goes from "idiot" to "savant" very quickly. PlayedForDrama since Barry had cleaned out Cedrick "Rick" Hawks at poker, and Barry told Rick, "Those hands were golden" when Rick thought Barry cheated.
* In a classic Saturday Night Live sketch, Phil Hartman plays Ronald Reagan as a friendly, slightly dim old man for the cameras and the public, but a genius mastermind behind closed doors, including the ability to do complex calculations in his head.
-->'''President Reagan:''' Bye bye! ''(Girl Scout exits Oval Office)'' Okay, back to work! ''(staff re-enters)'' Afghanistan needs more money. We've got $65.2 million tucked away in Zurich. Now, if we hold it there for another 30 days, at 7.28% interest, that's.. roughly.. $400,000.\\
'''Staffer #1:''' ''(with calculator)'' $397,200..\\
'''President Reagan:''' .. and 85 cents! I know! Don't waste my time! But.. if we take out only $20 million, we lose.. let's see, let's see.. that's..\\
'''Staffer #1:''' $121,800..\\
'''President Reagan:''' and 16 cents! Thank you so much!
[[/folder]]

[[folder:Tabletop Games]]
* ''TabletopGame/{{GURPS}}'' has the advantage Lightning Calculator to simulate this; the second level of it allows the character to do things like high-level engineering design in their head instantly.
* The Talent "Lightning Calculator" in HeroSystem lets a character do things like calculate an approach orbit for his spaceship in twelve seconds. Simpler calculations such as multiplying 4824 by 5933 would only take one second.
[[/folder]]

[[folder:Video Games]]
* ''VideoGame/TheWorldEndsWithYou''
** Sho Minamimoto, to the point of almost having the whole trope named after him. It even carries into his ''stats''. His HitPoints are 3141 when you fight him at the end of [[spoiler:Week 2]], and his [[spoiler:Taboo Form HitPoints]] are 5926. Put them together and tuck a decimal point behind the three and you have the first eight digits of pi.
** Neku could also apply for being able to belt out the square root of 3 at the drop of a hat ([[spoiler:during day two of the second week]], for those who wanted to know), but he could also have a calculator on his phone.
** Joshua is good enough with numbers to at least keep up with Minamimoto's ranting, [[spoiler:though his status as [[PhysicalGod the Composer]] ''might'' have something to do with this.]]
* Dmitri Petrovich of ''VideoGame/BackyardSports'' has this, coupled with the ability to use mnemonics to remember stats.
* Ran Yakumo of the ''VideoGame/{{Touhou}}'' series. [[http://en.touhouwiki.net/wiki/Article_and_Interview:_Ran She once calculated the width of the Sanzu River out of boredom]]. Note that the Sanzu River is the mystical river of the dead and that its width constantly changes whenever someone passes through it. In ''[[http://en.touhouwiki.net/wiki/Curiosities_of_Lotus_Asia%3A_Chapter_01 Curiosities of Lotus Asia]]'', when Rinnosuke first saw a computer and learned that it's used for, he interpreted them as being the outside world's version of {{familiar}}s like Ran, because they're slaves that are used to calculate things quickly. Of course, since a familiar's power is derived from its master, [[BrilliantButLazy Yukari Yakumo]] is even better at numbers than Ran, and Ran mentions that if Yukari wanted, she could have calculated the depth of the Sanzu River as well, even though it's known to be bottomless.
* N from ''VideoGame/PokemonBlackAndWhite''. He rambles about forumlas several times, and is seeking "the equation to change the world".
* Trevor from ''VideoGame/GrandTheftAutoV'' is. He knows exactly how much cargo comes through the port of Los Santos every year and exactly how much it's worth, and [[spoiler: in the "Subtle" approach for the final heist, mentally calculates how much the four tons of gold they're carrying is worth when told the individual value of each bar faster than the bank manager can]]. Wade even states plainly that Trevor is really good with numbers.
[[/folder]]

[[folder:Web Animation]]
* ''Machinima/RedVsBlue'' subverts this with Simmons proclaiming to be able to multiply large numbers in his head instantly. [[spoiler: He can't.]]
-->'''Grif:''' What's... 32 times 56?\\
'''Simmons:''' 31,452.\\
'''Sarge:''' Is that right?\\
'''Simmons:''' [[AppealToAuthority Yes]].\\
'''Sarge:''' That's pretty impressive!\\
'''Simmons:''' I know. It's a gift.
:: The correct answer is 1792. God knows [[AssPull where]] he got 31,452. Even 100 times 100 is only 10,000.
[[/folder]]

[[folder:Web Comics]]
* Laetre, a ''hamster'' showed some mathematical aptitude in [[http://www.hamletothehamster.com/2010/10/difficult-problem.html one comic]] of ''Hamleto the Hamster''.
* ''Webcomic/DubiousCompany'': This is the closest Future High Priestess Sal gets to superpowers, since [[ReligionIsMagic religion is NOT magic]]. She can rapidly calculate the [[DangerouslyGenreSavvy probability of anything]] based on [[AwesomeByAnalysis known factors]]. [[TearJerker Heartwrenching]] when she calculates the odds of escaping Kreedor's castle before her [[HumanSacrifice execution]] as [[DespairEventHorizon 0%]].
* ''Webcomic/TheOrderOfTheStick'': Kobold Chancellor Kilkil shows on [[http://www.giantitp.com/comics/oots0785.html several]] [[http://www.giantitp.com/comics/oots0847.html occasions]] that he's Good with Numbers. No surprise here, as he's the main accountant of a whole LawfulEvil [[TheEmpire Empire]].
* Parson Gotti of ''{{Erfworld}}'' isn't ''innately'' good with numbers. But he does have a pocket calculator, which in the game is regarded as something of a magic artifact, and is ''insanely'' good at calculating battle outcome probabilities (this is only partially due to the calculator). At least everything thinks he is. Probabilities being what they are, it's hard to prove one way or the other.
[[/folder]]

[[folder:Web Original]]
* Andi, the protagonist of ''Literature/LovelaceOneTwo'', goes from being a poor maths student to spontaneously able to solve problems as fast as she can speak or write at the beginning of the story.
* The Number Man of ''Literature/{{Worm}}'', who has this as an actual superpower, to the point where he can [[CombatClairvoyance calculate the exact probability of any outcome in the middle of combat]], and in his youth [[spoiler:was a legendary, undefeated member of the Slaughterhouse Nine]]. His power's broad scope also enables him to trivially crack encryption, model statistics on a large scale, and play the world economy like a fiddle.
[[/folder]]

[[folder:Western Animation]]
* Fenton Crackshell from ''WesternAnimation/DuckTales'' has the uncanny ability to precisely count any large quantity at a glance. Originally working at a bean factory as a literal bean counter, he is hired as Scrooge [=McDuck=]'s accountant because of his amazing talent (and because he works cheap). Later he defeats an alien computer by beating it at a counting contest. Fenton proved himself when Scrooge blasted him with a shotgun and Fenton ''counted the buckshot as they were fired.'' Scrooge was obviously stunned at this ability and had it confirmed when he suddenly tossed some coins into the air and challenged Fenton to assess their monetary value, Fenton's answer was correct ''to the penny''. Later, after Fenton took the phrase "liquid assets" too literally and [[ItMakesSenseInContext dumped all of Scrooge's money in a lake]], Scrooge threatened Fenton with his job if even a single penny was missing. Fenton slapped on a snorkeling mask, looked underwater for a few seconds, then resurfaced and rattled off a number in the millions that was only short by ''one cent''. [[spoiler:The missing penny was caught in his mask, so the money was in fact all there.]] In "The Attack of the Metal Mites," Fenton realizes something's wrong near the end--and a lightning-quick count has him realize he's a Metal Mite short of all of them (where even one Mite loose could reproduce and begin trouble anew). [[spoiler: He senses something about Scrooge, and taking a magnet, is able to attract the missing Metal Mite.]]
** Scrooge himself also qualifies. In another episode, he claims to have memorized the serial number of ''every dollar bill he's made.''
* Leopold "Butters" Stotch from ''WesternAnimation/SouthPark'' falls into this trope, multiplying two large numbers almost instantaneously in one episode.
* The janitor in ''WesternAnimation/{{Recess}}'' is revealed to be this when he easily solves Gretchen's math problem after school. He's eventually approached by the military and scientists... but he turns them down, saying he'd rather just be a janitor.
* Rosie Grape from ''WesternAnimation/VeggieTales'' is the youngest member of her family, and also the only one that knew what seventy times seven was.
* Humorously averted by Bender on ''WesternAnimation/{{Futurama}}'', even though he's a robot.
-->'''Bender:''' ''(doing calculations on a pad of paper)'' Aw, I need a calculator!\\
'''Fry:''' You are a calculator.\\
'''Bender:''' I meant a ''good'' calculator.
* Twilight Sparkle from ''WesternAnimation/MyLittlePonyFriendshipIsMagic'''. In part 1 of the season 3 premiere "The Crystal Empire", Twilight gives the square root of 546 as [[LudicrousPrecision 23.36664289109]] (which is only off because [[WritersCannotDoMath she should have rounded the last digit up instead of down]]).
* ''WesternAnimation/{{Grojband}}'': Trina loves math and numbers. Of course, she hides this side of herself behind her alter-ego, Trigonometrina, as she'd never admit it in public.
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[[folder:Real Life]]
* Taken UpToEleven in by Scott Flansburg as seen in ''Stan Lee's Superhumans''. He can do extremely complex math faster than a human using a real calculator.
* Carol Vorderman originally got the job on ''Series/{{Countdown}}'' in part due to her ability to solve the Numbers Round in her head.
** Her Australian counterpart Lily Serna is equally adept. Some of her solutions beggar belief.
* Kim Peek, the real life inspiration for {{Rain man}}.
* Arthur Benjamin is a Mathemagician, combining magic tricks with phenomenal mathematical ability. In his TED talk he squared a five digit number in his head correctly in just a couple of minutes, prompting a standing ovation.
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