I'm looking out for maths tricks, specializing in "Square of a number" Like how to find square of numbers after 30 within seconds. There must be some tricks. Because the multiplying takes time, and it's hectic, and yep, without using calculators! Squares of big numbers! like numbers after 30. Or any random number that appears.

Question

I'm looking out for maths tricks, specializing in "Square of a number"  Like how to find square of numbers after 30 within seconds. There must be some tricks. Because the multiplying takes time, and it's hectic, and yep, without using calculators! Squares of big numbers! like numbers after 30. Or any random number that appears.

anonymous · Answer

There's a TED talk about a guy that can do this really fast.

anonymous · Answer

TED stands for?

anonymous · Answer

So there ain't no tricks?

anonymous · Answer

It's a site where people talk about interesting Ideas. Here's the link: http://www.ted.com/talks/lang/en/arthur_benjamin_does_mathemagic.html

anonymous · Answer

Don't know if it'll help you though.

anonymous · Answer

No worries, thank you for the link Thomas. The question is still open guys! :]

kinggeorge · Answer

It might be helpful to memorize the squares of 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 200, 300 up to some point. Fortunately, these are relatively easy to memorize.

kinggeorge · Answer

Also, if you can get the rules down for polynomial expansion, that could be very useful. E.g., $$312^2=(300+10+2)(300+10+2)$$$$312^2=300^2+10^2+2^2+2\cdot(300\cdot10+300\cdot2+10\cdot2)$$$$312^2=90000+100+4+2\cdot(3000+600+20)$$$$312^2=90104+2\cdot3620$$$$312^2=90104+7240$$$$312^2=97344$$

kinggeorge · Answer

Other than that, memorization and practice are the best way to go.