Mental Maths

[ElRaja]

Anyone here practise mental maths? i know in modern day its pbly not as useful with calculators in everyones phones, but still....

i used to be good when i was younger, then i got rusty, am trying to practise my way back to getting better.

maybe if theres a few other fellow geeks, can discuss tips and tricks to attempt to defy the years and get better at it.

 

[Tubs]

Hmm, interesting thread. I have gotten worse too, despite being in mathematical uni courses (computer science, robotics, AI, etc), but I suppose when you do higher level maths (though I never did anything comparable to a maths/physics degree), you mainly focus on abstractions and showing a solution can be found, or modelling a solution with mathematics, rather than solving.

Though, I'd still say I'm slightly above average. Methods I usually use are 'splitting' numbers, so if you want to add 13+37, I'd do 37+3, then add the 10, as it's easier and quicker to add 10 to a number, and to add numbers when they're rounded to the nearest 0. I also split up numbers when I multiply too, as it makes the calculations simpler usually, then add them up. Can't think of anymore 'tricks' at the moment, but there's likely a lot of resources online.

 

[pillionrider]

A thread calling on advice for mental gymnastics might get more replies

 

[CricketCartoons]

Mental arithmetic you mean. Maths is for adults, arithmetic for kids.

 

[rockyboy2018]

My German professor for Maths is a Ph.D. He always tells us to use a calculator it can not be deceived. But, with the mind, you can not always trust its ability. It can play tricks. 37+3 could well be 50 if you are in a hurry.

 

[Saj]

I used to be able to add up my parent's shopping at the supermarket to the penny in my younger days.

Nowadays I can still add up my own shopping to within a small amount, so I'm still not bad.

 

[TSA321]

Was very good at it when young thanks to Kumon. Still ok at it.

 

[Tubs]

Mental arithmetic you mean. Maths is for adults, arithmetic for kids.

Not to be 'that guy', but since you already tried to be 'that guy', I will correct you. Arithmetic isn't simply adding and subtracting integers. Number theory, an advanced mathematical topic usually studied in 2nd/3rd year maths (and sometimes computer science) courses is an example of arithmetic, so is floating point arithmetic (concerned with the trade-off and precision of using arithmetic with floating point numbers in programming), arithmetic series, etc.

 

[CricketCartoons]

Not to be 'that guy', but since you already tried to be 'that guy', I will correct you. Arithmetic isn't simply adding and subtracting integers. Number theory, an advanced mathematical topic usually studied in 2nd/3rd year maths (and sometimes computer science) courses is an example of arithmetic, so is floating point arithmetic (concerned with the trade-off and precision of using arithmetic with floating point numbers in programming), arithmetic series, etc.

Number theory is not an example of arithmetic. Number theory is a vast subject. Ever heard of algebraic number theory? Fermat's last theorem is arithmetic? Dirichlet's theorem is arithmetic?

go to next door, please.

 

[ElRaja]

Hmm, interesting thread. I have gotten worse too, despite being in mathematical uni courses (computer science, robotics, AI, etc), but I suppose when you do higher level maths (though I never did anything comparable to a maths/physics degree), you mainly focus on abstractions and showing a solution can be found, or modelling a solution with mathematics, rather than solving.

Though, I'd still say I'm slightly above average. Methods I usually use are 'splitting' numbers, so if you want to add 13+37, I'd do 37+3, then add the 10, as it's easier and quicker to add 10 to a number, and to add numbers when they're rounded to the nearest 0. I also split up numbers when I multiply too, as it makes the calculations simpler usually, then add them up. Can't think of anymore 'tricks' at the moment, but there's likely a lot of resources online.

yeh i pretty much do the same tbh

i used to work at this place when i was younger (grad days internship) where they gave a number problem, 6 one to two digit integers, and a random 3 digit number like the countdown game, and usually they had it at 445 and said no one leaves till u have the answer.

was horrible, bt rewarding to get right.

 

[ElRaja]

A thread calling on advice for mental gymnastics might get more replies

no one would admit their expertise...

 

[Tubs]

Number theory is not an example of arithmetic. Number theory is a vast subject. Ever heard of algebraic number theory? Fermat's last theorem is arithmetic? Dirichlet's theorem is arithmetic?

go to next door, please.

Yes, it is vast. But it's origins are in arithmetic. Much of the number theory problems are expressed purely in arithmetic, and Fermat's last theorem's whole purpose is to show how more sophisticated methods are required for seemingly simply, arithmetic problems. It used to simply be referred to as 'arithmetic', and even is so in some texts. Take the L man, you tried to sound smart but failed. You also didn't contest floating point arithmetic, arithmetic series and geometric progression. Even if I concede number theory, which I don't, you claim that 'arithmetic is for children' is wrong.

 

[Tubs]

Number theory is not an example of arithmetic. Number theory is a vast subject. Ever heard of algebraic number theory? Fermat's last theorem is arithmetic? Dirichlet's theorem is arithmetic?

go to next door, please.

Hahha, also I wasn't 100% sure so I had to look it up, but Dirchlet's theorem's is an arithmetic progression. You love to see it, folks.

 

[CricketCartoons]

Hahha, also I wasn't 100% sure so I had to look it up, but Dirchlet's theorem's is an arithmetic progression. You love to see it, folks.

The algebraic foundations of the theorem are lost on you. Cryptography must also be arithmetic for you? Lol at this wannabe. For a moment I was worried that a person who got a degree in maths is so ignorant about his field, but it is a relief to know you are only an internet mathematician (sorry arithmetician).

 

[CricketCartoons]

Yes, it is vast. But it's origins are in arithmetic. Much of the number theory problems are expressed purely in arithmetic, and Fermat's last theorem's whole purpose is to show how more sophisticated methods are required for seemingly simply, arithmetic problems. It used to simply be referred to as 'arithmetic', and even is so in some texts. Take the L man, you tried to sound smart but failed. You also didn't contest floating point arithmetic, arithmetic series and geometric progression. Even if I concede number theory, which I don't, you claim that 'arithmetic is for children' is wrong.

You took arithmetic is for children literally, that shows you lack the sophistication needed to learn the higher abstractions of maths. Go and learn the tables. That must be the most sophisticated maths (sorry arithmetic) you will ever do.

 

[Tubs]

You took arithmetic is for children literally, that shows you lack the sophistication needed to learn the higher abstractions of maths. Go and learn the tables. That must be the most sophisticated maths (sorry arithmetic) you will ever do.

Oh no, don't backtrack now. You said what you said, and you're wrong.

I never said that I study especially sophisticated maths, but you came in spewing falsities. It's hard to quantify the level of sophistication of maths, but as someone in the intersection of computer science, engineering, robotics and (especially bio-inspired/evolutionary)AI, I definitely don't require incredibly sophisticated maths, but a sufficient level of linear algebra, calculus, differential equations (including Laplace transforms, Z-transforms, and probably more as I'm only halfway through the course), (mathematical) statistics and probability (probability distributions, probabilistic machine learning models, Bayesian filters), mathematical optimisation (mainly convex programming and metaheuristics),discrete mathematics (graph theory, logic, boolean and relational algebra) dynamical systems (including non-linear dynamics, chaos, and complex systems theory in general). Throw in programming (in python, C, C++, R, Matlab and a bit of assembly- chuck in SQL too even though it's technically a querying language) and basic electronics (very basic). So there, while I'm not a maths whizz by any means, I know a little.

Even if I had failed GCSE maths with no other mathematic qualifications to my name, your statement would be false still. Hope that helps, please humbly accept you were mistaken and we can be done with this.

 

[CricketCartoons]

Oh no, don't backtrack now. You said what you said, and you're wrong.

Nice word salad with no substance. You believe that number theory is arithmetic, but number theory cannot stand without algebra. Go and first learn the difference between arithmetic and algebra before you can even be taken seriously. shoo off.

 

[Tubs]

Nice word salad with no substance. You believe that number theory is arithmetic, but number theory cannot stand without algebra. Go and first learn the difference between arithmetic and algebra before you can even be taken seriously. shoo off.

Good one, I even said that if I concede number theory, my point still stands. But number theory's foundations are in arithmetic, Fermat's last theorem is an example of how seemingly simple problems framed in arithmetic require more sophisticated methods- paraphrased from Wiki. If arithmetic is only for children, why do some arithmetic problems require such profound methods to solve? Your very mention of Fermat's last theorem defeats your own point. Number theory was initially only concerned with arithmetic problems, obviously it has branched into analytic number theory, algebraic number theory, and many other applications I don't know of, but that doesn't undermine what number theory originated as. It was even synonymous with 'arithmetic' or sometimes called 'advanced arithmetic', but you won't accept that either.

You also called me an 'internet mathematician', that's far more than what I said about myself- I never claimed to be a mathematician. I am pretty bad at proof-based problems, and my mathematical ability is about bang average for a (non-mathematic and non-physics) STEM PhD student. I can accept my shortcomings, but you can't accept that you were wrong and are backtracking. You were being unnecessarily pedantic when you (falsely) claimed that arithmetic is for children, but when I return the pedantry and am actually correct, you can't accept it.