My daughter recently took an undergraduate course in { Abstract Algebra } ,
Here is a quick explanation .
First , we bring back the { Characteristic Equation } for the { Prime Numbers } 3 , 5 , 7 , 11 , 13 & 17 .

And we note that this equation is of the format :

And the { Base Solution } to this type of equations is always :

Let us now multiply the { Characteristic Equation } by [ 2 ] , to yield :

Expanding terms , we have :

Thereupon yielding the equation :

Let us now multiply the { Characteristic Equation } by [ 3 ] , to yield :

Expanding terms , we have :

Thereupon yielding the equation :

Thus , every value of { [ Z ] modulo 225,255 } , is always expressible by a unique { 6-digits code } :
| Value of Z |
Value of A |
Value of B |
Value of C |
Value of D |
Value of E |
Value of F |
|---|---|---|---|---|---|---|
| 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| 1 | 2 | 1 | 4 | 2 | 8 | 13 |
| 2 | 1 | 2 | 1 | 4 | 3 | 9 |
| 3 | 0 | 3 | 5 | 6 | 11 | 5 |
And all [ codes ] are expandable via the { Characteristics Equation } :
We have therefore set-up a { coding system } for { modulo [ L.C.M. ] } .