Arthur Benjamin: Lightning calculation and other “Mathemagic” In a lively show, mathemagician Arthur Benjamin races a team of calculators to figure out 3-digit squares, solves another massive mental equation and guesses a few birthdays. How does he do it? He’ll tell you.TEDTalks is a daily video podcast of the best talks and performances from the TED Conference, where the world’s leading thinkers and doers are invited to give the talk of their lives in 18 minutes — including speakers such as Jill Bolte Taylor, Sir Ken Robinson, Hans Rosling, Al Gore and Arthur Benjamin. TED stands for Technology, Entertainment, and Design, and TEDTalks cover these topics as well as science, business, politics and the arts. Watch the Top 10 TEDTalks on, at http

27 thoughts on “Arthur Benjamin: Lightning calculation and other “Mathemagic”

  1. For the second trick, the number they multiplied by was 8649 which is a multiple of 9. That means whatever they multiplied by would add up to a multiple of 9 (9 divisibility rule)
    He just added the numbers they gave him and saw what he needed to get to 18 or 27 or whatever and said that was the missing number… good trick :D

  2. I like how you’re just reiterating what I said.
    There are so many more things to being a physicist than math,so,well he can do basic math in his head, it still has very little application to physics,I never said you dont use math in physics, I just said it’s not as important in the equations.

  3. Math is essential for Physics. If you can’t do advanced math, you can’t be a physicist. Plain and simple. It makes up about half of it’s application. No Physics isn’t ABOUT math but Physics has everything to do WITH math and vice versa.

  4. I’m puzzled, I’m doing homework for my class at the U of U “Math the language of Physics”, I’ll tell my professor to fuck off and it’s useless because you said so. Thanks for saving me wasted hours.

  5. Do you even know the definition of physics?! While, you can use math to solve physics equations, that is nothing, I’m not sure you should EVER consider being a physicist please.

  6. He fucked up at 4:01, answer is 521,284 not 513,284. No crit. at all tho, this man is absolutely amazing. The only “magic” I can do is making my thumb look like it’s coming off and my niece figured that one out after a couple of minutes

  7. Na, you can easily calculate all the stuff he was doing.
    The day of the week trick is very easy to learn, took me like 4 hours of practice when i was 7 years old.
    SUPER awesome bar trick :)

  8. All of this was basic math with nothing more fancy than basic math for everything, even the Day of the week trick is done with simple math. And association of months, days and years with numbers.
    Anyone can learn how to do it with some simple mnemonics to help remember the numbers, if you need those.
    But this guy’s memory is VERY good, he has much better stuff than on this video.
    This video just touched what he can actually do :D

  9. Dude, I’m an engineering student. Anything above an entry level high school physics course is all differential equations and calculus. To start with you have to derive all of the equations you learned in Physics “101″ with calculus and prove them mathematically.

    Vedic math isn’t just about multiplying large numbers either, that’s all this guy is doing because it impresses the audience, but you can do every form of arithmatic in your head if you learn it right.

    You can’t do physics sans math.

  10. And no, to solve the equations that they use in physics, you need to know more than just how to multiply and divide, the equations are clearly not what you think they are.

  11. Physics has nothing to do with math….by the very definition of physics he would know nothing of it.
    Differential equations is not at all what physics is about, you can use math in physics but, just because he can multiply in his head ( like I said so many times) has nothing to do with physics, if someone knows nothing about math doesn’t mean he doesn’t know anything about physics, you need to know some math to do physics, but not just how to multiply large numbers in your head.

  12. But… physics IS math. It’s simply applied mathematics. Someone who knows nothing about math would know nothing about physics. Have you ever solved differential equations before? It’s all multiplication and division (and admittedly algebra triicks). Practically every derivative and indefinite integral can be figured out by multiplication and division (and logarithms). I didn’t say he was a genius at theoretical physics, I said he should be working on it.

  13. You realize, he probably knows nothing about physics, a mathematician isn’t good at physics just because he is good at math, like I said before, just because he can do MULTIPLICATION in his head, doesn’t make him a genius at theoretical physics.

  14. It would certainly help if he didn’t need the calculator. Plus, squaring large numbers comes up alot in physics. Calculus and Differential equations are not “hard complicated” math either, they are just simple processes repeated multiple times. The ability to remember as many digits as you have to to perform vedic math would alone be quite useful in theoretical physics. Calculators are just making people dumber.

  15. You do realize that he is not doing any hard complicated math, he is just doing multiplication in his head, I doubt knowing how to square a 5 digit number will help him in physics when an actual physicist could just use a calculator.

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