Interview by Justin Goodlett (and win $20!)
posted 4 years, 1 month ago // 12 comments // comments are closed
I’m
excited to announce my
first ever interview by Justin Goodlett of SkinnyJ.
Previous interviewees include Jon Hicks and Andy Arikawa — needless to
say I find myself in good company. I answer questions about design, aesthetics,
usability, Jakob Nielsen, inspiration and how I became to be a designer. Enjoy!
But wait…
There’s more! In the interview
I challenge readers to calculate my age using a mathematical formula. The first
reader to post a correct answer along with a rationale of the calculation in
the comments will win a $20 gift certificate
from amazon.com. That’s as many dollars as necessary to buy a copy of
the new required reading by the folks at 37signals
entitled Defensive Design
— heck, you’ll even have enough left to grab a beer at your local
pub.
Update: There are some mucho smart and especially lightening fast people on the web. Damn. You’ve guessed it: the $20 gift certificate has been won, already. Congratulations to both Shaun and David for the answers. They both get $20. So, what did you think of the interview? Discuss!
You’re 24.
Oops, forgot the rationale:
Because Google Calculator said so. ;-)
Sheesh… one day I’ll learn to click on hyperlinks in order to post in the correct comments. I’m such a dumbass. Feel free to delete these comments. Or leave them up for the amusement of others. It’s your call. :-/
54^7 = 1338925209984
1338925209984 mod 65 = 24
if that’s not enough detail:
the ^ means the first raised to the power of second
mod means the remainder when the first is divided by the second
Very well done. Calculators make life easy. Now the hard part…
Although you were all able to perform the calculation you didn’t provide me with a satisfactory rationale. I was expecting the calculation itself to be solved rather quickly.
However I need an explanation of how modulo (mod) works and not just a description of the formula. Include a simple example along with a summary in words of how it is actually being calculated and the $20 is yours! But don’t forget to post it on SkinnyJ.
Ok, that was a cool contest. Funny thing is I majored in math and even completed 2 semesters of calculous with the local community college in my last year of highschool, yet I don’t ever remember seeing ‘modulo’. Not that I didn’t, I just don’t remember. Of course it has been a few years since I used any of that stuff.
Anyway, just wondering if there is a easy equation to find how anyones age would be respresented like that. I’m looking for a way to give my age (or anyones) and have it spit out the equation representing that age.
[I thought I’d post this here too.]
For a non-calculator solution (if anyone’s interested),
If a (mod x) = b (mod x)
and c (mod x) = d (mod x),
then a*c (mod x) = b*d (mod x).
Note also that negatives are permissible in modulo arithmetic, and any numbers with the same remainder in the corresponding base are equal (congruent). In other words,
54 (mod 65) = -11 (mod 65).
Continuing (all in mod 65),
54^2 = (-11)^2 = 121 = -9
54^4 = 54^2 * 54^2 = -9 * -9 = 81 = 16
54^6 = 54^4 * 54^2 = 16 * -9 = -144 = -14
54^7 = -14*-11 = 154 = 24
Therefore, DH is 24.
Some might think that stating my age with a mathematical formula is rather esoteric. But I thought it would be a nice challenge (it turned out to be to easy a challenge). So why modulo you ask? What’s so great about it?
I find numbers fascinating. Prime numbers, Fibonacci sequence, Caesar cipher (simple shift cipher) and things alike. Cryptography plays an important role in technology security (online, offline and basically everywhere). Modulo aritchmetic is used in public key cryptography: RSA. Of course there’s much more to cryptography than just modulo arithmetic.
I’d like to thank James for his non-calculator solution since it nicely shows how it works. I always use a simple example to explain how it works. Take 3^2(mod)2 for example.
3^2(mod)2 = 9(mod)2
2 * 4 = 8 (2 fits 4 times in 9)
9 - 8 = 1 (which is the remainder)
therefore: 3^2(mod)2 = 1
I think this should be enough mathematics for a whole year. Back to important things! Back to design and interfaces!
For furture reference, the easiest way to mark up Modulus is with a % sign. ie:
2%1 == 1
or
(3^2)%2 == 1
In addition, modulus is really easy to figure out without a calculator. Simply subtract the modulus number until the reult is less than the modulus operator. This method seems a little easier than the one posted a few comments above by James. A few examples:
9%2 = 1
-
9-2 = 7 (7 < 2) { false }
7-2 = 5 (5 < 2) { false }
5-2 = 3 (3 < 2) { false }
3-2 = 1 (1 < 2) { true }
5%3 = 2 — 5-3 = 2 (2 < 3) { true }
7%2 = 1 — 7-2 = 5
5-2 = 3
3-2 = 1
19%4 = 3 — 19-4 = 15
15-4 = 11
11-4 = 7
7-4 = 3
For a negative number, I imagine you can just drop the negative operator (work on it’s absolute value).
Didier - I am sure the figures are perfectly rounded!
ooudfaqmhc bjaf.