Jack Aidley
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 Sep24 awarded Autobiographer Jun30 comment Subtraction of a negative number Not sure why this got downvoted, I think it cuts to the chase rather neatly. May20 awarded Peer Pressure May19 awarded Editor Apr28 comment A function such that $f(f(n)) = -n$? Signed integers are not actually stored with a sign bit on any modern computer. Instead the MSB is treated as a negative value (a method called Two's complement). This gives much easier implementation of basic arithmetic and has only one representation of zero. Apr28 comment A function such that $f(f(n)) = -n$? @Seth: Numbers in computers are stored in Two's complement. 31-bits are as you would expect and the highest bit means $-2^{32}$. The method you describe is One's complement and it is not used as it gives two representations of zero. Apr28 comment A function such that $f(f(n)) = -n$? @TomCollinge: I think you mean $[-2^{31}, 2^{31})$. The lowest representable number in 32-bit twos complement is -$2^{31}$ and the highest is $2^{31}-1$. Jan30 awarded Yearling Aug21 answered math fallacy problem: $-1= (-1)^3 = (-1)^{6/2} = \sqrt{(-1)^6}= 1$? Aug6 comment What would have been our number system if humans had more than 10 fingers? Try to solve this puzzle. The next interesting question is: what we can we conclude from this information about Martians? The first natural conclusion is that Martians cannot be symmetrical about any number of axes other than thirteen- since 13 is prime - unless, that is, they have a single fingered appendage, which would have to be located along the axis of symmetry. May3 awarded Critic Apr14 awarded Nice Answer Apr5 awarded Teacher Apr5 answered There are no bearded men in the world - What goes wrong in this proof? Mar7 comment What was the first bit of mathematics that made you realize that math is beautiful? (For children's book) What if I am 4? Feb20 comment Is it true that the book 'Calculate Primes' has found the pattern? Looks like it's a version of the sieve: tysondw.blogspot.co.uk/2009/01/… Jan30 awarded Supporter