[BlindMath] Question for y'all.

[Ray McAllister]

Hi, okay, so I'm going to assume that a number of us are on various
assistance programs like Medicaid.  

 

Now, I was learning in an abstract algebra book about these error-checking
systems, where the digits of a number will be rigged so that the sum of the
digits, when run through some algorithm, will be a remainder of 0 if divided
by something.  ISBN numbers, for books, for example, run like this. 

 

The first 10 digits,  

 

D1, d2, d3, . d10, for their digit numbers.  

 

We do a dot product 

 

(d1, d2, d2, . d10) * (10, 9, 8, 7, . 1), and if the last digit needs to be
10, we put X there.  That is all to be id 0 mod 11.  

 

So, for the first 3 digits of most books, 987.  

9*10 + 8*9 + 7*8 = 218, which isn't anything, but keep going, and it will
work. 

 

So I ran my Michigan Medicaid, 10-digit number, through the same algorithm,
and the result was also id 0 mod 11.  

 

This method prevents single digit errors, orerrors in switching digits. 

 

I wonder if any of you have Medicaid numbers, especially if you're in
Michigan, that do this, also, or if mine is just random chance. 

 

Ray.