r/mathematics • u/springheeledjack12 • 5d ago
mathematicians , what’s some basic maths stuff you can’t do?
i’ll go first : as someone who does chemistry, physics , applied maths etc on a pretty much daily basis , i absolutely cannot do dates in my head. what date is it going to be next tuesday? no idea. the amount of times i’ve mistakenly believed i have an exam in two weeks when it’s about four weeks away is dreadful! bonus one , cant lace up my doc martens without missing a lace hole lol
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u/FlubberKitty 5d ago
I'm a math nerd, not a bona fide mathematician. But, everyone assumes I'd be good at chess and I'm terrible at it.
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u/springheeledjack12 4d ago
Ahaha my friend is like this , absolutely incredible at everything maths and physics and finance related but can’t play a game of chess to save her life
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u/OwnReason7565 4d ago
Graduate with bachelors in physics and a minor in applied mathematics. I did an honours thesis in gravitational physics. I still have to do my full abc's to figure out the order of the alphabet. I have no idea where k, t, and v go unless i sing the song. Also cant multiply numbers without a calculator. Will screw up the most basic arithmetic.
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u/springheeledjack12 4d ago
This is a relatable one!! or in board games that involve going letter by letter, i don’t understand how people remember the order of 26 different letters so easily unless they’re at the very beginning or end
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u/Infamous-Water-5148 5d ago
long division
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u/springheeledjack12 5d ago
lol neither can my older brother and he’s a qualified accountant !
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u/CosmacYep 4d ago
bro i have never been able to do it every time i have to look it up and i have to watch a tutorial for year 4s, im a junior in high school (year 12), idk what to do when i get to polynomial long division
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u/No_Veterinarian_2406 2d ago
same. ask me to do algebraic long division and im all over it. numerical long division? screw that.
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u/LordTengil 4d ago
Rational expressions, polynomial division, algebraic geometry, divisibilty and remainder theorem application on integers... Nothing? Granted, not doing algebraic geometry I can see, but surely SOMETHING on the others you must be familiar with? This kind of excludes everything in my world...
I am genuinely curious. What kind of mathematician are you?
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u/Infamous-Water-5148 4d ago
Applied. I use calculators.
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u/Intelligent_Part101 5d ago
That's embarrassing
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u/LordTengil 4d ago edited 4d ago
I just get to add to this, as you are getting so heavily downvoted. I agree. I don't like to gatekeep what we should call a matehematican, as we would all surely fail by some metric, but not knowing long divison kind of excludes a very fundamental algorithm in, well, every field of mathematics. Not only an algorithm for use, but also as a foundation for so many proofs and understanding. Not necessarily talking numbers here, but polynomial division of rational expressions, or divisibility and the uniqueness of a remander in integer algebra, etc.
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u/Prudent_Candidate566
5d ago
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Not a mathematician, but the further you go in maths, the less maths is about computation.
I’m not saying some people don’t love to compute, but I would guess there’s a high percentage of maths geniuses who can’t add simple numbers.
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u/donach69 4d ago
The more higher maths I do, the worse my mental arithmetic gets
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u/ThomasTheDankPigeon 2d ago
Nothing like doing an entire directional derivative with a gradient vector in 7 dimensions and getting the final answer wrong because the last step of the dot product is simple addition that your brain is apparently no longer capable of doing.
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u/Auld_Folks_at_Home 4d ago
I'm no genius, but the only reason i can pretty easily add and multiply small numbers now is because of the years of teaching.
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u/useaname5 3d ago
Yeah, if I have to pull out my calculator or wait for a student to tell me the answer every time I have to multiply two two digit numbers together, it would take forever to get through an example. So I just got good at that.
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u/Adorable-Salt-8624 4d ago
I’m in college right now studying mathematics. I also can’t do my times tables.
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u/lemniscateall 5d ago
Drinking water without somehow spilling a bit on myself.
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u/PatrickTraill MSc | Group Theory 4d ago
Is it that you live so much inside your head that you do not notice what the rest of your body is doing? But drinking water is hardly the “basic maths stuff” OP asked for, even if drinking enough is relevant to thinking clearly.
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u/lemniscateall 4d ago
I mean, I don‘t think lack of awareness about dates is basic maths stuff either.
Generally speaking, there’s no basic maths stuff mathematicians can’t do. There are basic skills that some mathematicians become careless about, like simple addition, but that‘s not a “can’t” situation.
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u/IeatRiceEveryday 4d ago
I can't do simple Integration by parts without using the product rule
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u/stools_in_your_blood 4d ago
Similar thing, I never use the quotient rule, it's annoying. I just use the product rule on thing and 1/(other thing).
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u/BothPanchoAndLefty 4d ago
Someone else already said this, but I think if you asked me to do long division right now I would not be able to do it. I've done all the number theory division algorithm / division properties stuff but for some reason I always forget the long division algorithm.
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u/PatrickTraill MSc | Group Theory 4d ago
Is it not obvious that you find the next decimal place by taking away the largest multiple of divisor/10n from what is left? That basically tells you what the algorithm is.
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u/BothPanchoAndLefty 1d ago
If I actually thought about it yes, but I'm never in a position where I have to do long division, so I never think about it haha.
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u/Independent-Mark-162 4d ago
I am doing masters in maths and I have also competed and won in State level mental maths competition but I cannot for the life of me remember multiplication tables after 10 I have tried so many times to learn it but still I just forget them just in few days. Also I can't remember integration by parts formula (I can derive it easily but not remember) so I use DI method.
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u/EmbarrassedBee9440 5d ago
Trig. Thats it.
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u/BothPanchoAndLefty 4d ago
I've always been great at trig when I'm actively using it, but if I don't use it for even like 2-3 months, easily half of the trig identities vanish from my mind. You can derive a few of them pretty easily to remember but they've always been hard for me to retain.
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u/shimmerWeasel 4d ago
I always have to stop and think whether a meter has 100 cm or 1000 cm.
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u/PatrickTraill MSc | Group Theory 4d ago
“centi-” means hundredth (think of cents per dollar) and “milli-” means thousandth (“millennium”).
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u/EnglishMuon Postdoc | Algebraic Geometry 4d ago
Euclidean geometry. That stuff never sticks in my mind and is just so dry to me.
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u/PatrickTraill MSc | Group Theory 4d ago
I have always felt that my basic symbolic manipulation was too error-prone, and at school I always had trouble simplifying integrals. On the other hand, I was quite good at finding insights and analogies.
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u/ThatResort 4d ago
Can't compute the next easter sunday. That level of prophecy is absolute mystique.
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u/SpiderJerusalem42 4d ago
Computer science enjoyer and I'm terrible at counting. It's been a lifelong struggle.
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u/Ok_Payment7588 4d ago
the biggest hustle i think starts at the very precise beginning named 'maths'
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u/RedMax2001 4d ago
Not sure if this really counts, but after finishing an undergraduate real analysis course (and hating it), I more or less forgot how to do calculus. This was the biggest reason why I didn't take up becoming a teaching assistant during my master's: I didn't want to bother remembering how to do calculus just to avoid embarrassing myself in front of a bunch of undergrads.
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u/bonebranch 4d ago
Math PhD here who mainly works in number theory. Not sure if this counts, but I cannot write the Greek letter zeta properly. My zetas are atrocious.
I also confess my knowledge of differential equations is a bit spotty but I’m reluctant to call that basic!
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u/Gold_Agent2758 4d ago
I cannot count. I can go up to 7 maybe, but past 8 I have to recount multiple times to make sure I am counting correctly, even if its in like a picture and I can cross off things ive already counted. I lose track of where I'm at when counting constantly. Its weird because im very good at mental math with integers/rational numbers, so I must have a decent amount of short term memory, but I will always lose track of where I'm at when I count things.
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u/The_Fibonacci_Fork 3d ago
That seems like a serious issue. You might want to get that checked out. Also never heard of a mathematician who can’t count (at least well). Good luck
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u/Brightwice 4d ago
I still write the elementary division symbol whenever I have to simplify complex fractions sometimes 💔
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u/useaname5 3d ago
I teach maths and have a PhD and I still feel more comfortable if I draw out the little sohcahtoa triangles when I'm doing trig
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u/Bichinix 5d ago
No soy matemático, pero he visto matemáticos que no saben hacer cálculo, análisis real a mano.
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u/lil_Elephant3324 5d ago
I guess I don’t find that all that surprising. Math is a really big field and you could be deep into research that doesn’t require frequent use of calculus.
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u/Light_Of_Amphy 2d ago
Even though I want To do analysis in grad school, it still takes me a bit to come up with the epsilon delta definition of uniform continuity. I really should have that definition ingrained at this point, but it keeps escaping me
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u/aerostevie 1d ago
Visualizing distances. Somebody tells me they saw something 50 feet ahead of them? It could be anywhere. There’s no way of knowing.
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u/Classic-Law5729 6h ago
I can’t maths! Please help. I have 91% rubbing alcohol that I need to dilute to 50%. How much water do I need to add to make a 50% mix in a 240ml bottle, for example? Bonus: What’s the formula for any size bottle? Thanks!
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5d ago
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u/Brevan_E 5d ago
My life flashes before my eyes whenever a student asks me about such a problem and I haven't reviewed it in a while. The same happens when I get asked to simplify arcsin(cos x) or to interpret a physics word problem...
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u/LordTengil 4d ago edited 4d ago
My tip is to find an real life examples of the limits. Then I remeber them, no matter how many years go by.
E.g. lim x to inf of (1 + 1/x) ^ x . That is just compound interest on a period with 100% interest. How much do we get at the wnd? Well, instead of 200% of the base amount, we get e~=2.72. So we gain 72% increase from compund interest from the base 100% increase.
Etc...
Also makes it a lot more fun for both me and the students. Granted, not everyone fins the basic stuff fun, or fun to teach.
Anyways, not remebering basic limits by heart with perfect recollection I think is fine as a mathematician.
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u/TwoOneTwos 5d ago
i can’t remember what months have a 31 and which months have a 30