Certainly, ShadyLady and thanks for the question.
At least here I know more about it. The root calculation is using the same base as "standard sum chart" that you can find here:
http://www.lotto-logix.com/txthouse/pick3sums.html
Roots are another way of combining numbers together. While sums contain different numbers of sets (e. g. there 3 sets with the sum 1 but there are 75 sets with the sum 13 and 36 with the sum 20), roots (ot this version of the roots) have all the same number of sets included (besides root zero that is).
There are exactly 111 sets with the roots 1 to 9 plus one set with the root 0 (apparently the set 000).
Calculation:
here the calculation that is used to come up with the root.
sum of 784 = 7 + 8 + 4 = 19
sum of 19 = 1+9 = 10
sum of 1+0= 1. This is the root.
sum of 172 = 1 + 7 + 2 = 10
sum of 10 = 1+0 = 1
sum of 1 = 1. This is the root.
So the root is really the "sum" of the "sum" of the "sum".