I've read this three times, and I confess I still don't understand what Excess-3 is or how it's encoded. While this isn't my area of expertise, I have a degree in computer science so one might reasonably assume this should be trivial to comprehend.
This seems to be a challenge for Wikipedia: certain types of technical and mathematical material are explained in terms that are esoteric enough ("pseudo-tetrade"?) that only the people who already understand them can follow the explanation.
A decimal digit is encoded in 4 bits as its usual encoding plus 3. Thus 0 is 0011 and 5 is 1000.
Some nice things which happen are…
- the carry bit out of your 4 bit adder is the carry bit from the decimal add. (Your two digits plus their two threes makes sixteen)
- you never have more than three identical bits in a row (5 if you concatenate digits). This can be important for any kind of self clocked data stream. Too long without transitions and you aren’t really sure how many bits the sender meant because your clocks are a little off.
- it has a reasonable way to represent negative numbers.
One significant downside was that on each add you had to take a 3 back out.
I think the Fibonacci number page isn't a great example since it explains the middle school version in the first few lines. It only goes into depth much later.
The Excess 3 page however has a really complicated first paragraph where only about 5 words even attempts to explain what it is (a self-complementary BCD) and then again uses 2 terms that you might not know. BCD has a useful link to another article but what does self-complementary mean? I only see a mention of ones complement all the way down in the motivation. It also fails to explain how addition/subtraction work so you have to figure that out yourself.
After a good amount of reading I could understand it and why it's actually cool but by god it wasn't as easy as it could have been.
Content that adjusts to the user's knowledge level would be a ton of work and definitely overkill for this issue. There is currently almost zero feedback between readers and writers of Wikipedia articles because most of the readers don't know how to edit the page or the talk page.
You could get 50% of the benefit by just having a non-annoying way for the reader to indicate they are confused (and, ideally, that the page is too slow/elementary). Then you could just plot a heat map to see the words/sentences that are causing all the trouble.
This seems to be a challenge for Wikipedia: certain types of technical and mathematical material are explained in terms that are esoteric enough ("pseudo-tetrade"?) that only the people who already understand them can follow the explanation.
Even something simple enough to be taught at middle-school level (e.g. Fibonacci sequence) becomes a page of dense mathematics on the Wikipedia page: https://en.wikipedia.org/wiki/Fibonacci_number#Matrix_form
I wonder if this can ever be addressed with some form of adaptive content?