## Sum Root

This
filter accepts tickets with selected *sum root* values. Sum root is a
single digit number ranging from 1 to 9. It is calculated from
arithmetic sum of ticket's main numbers by repeatedly summing the
digits of the sum value until only a single digit number is left.

### Example

Ticket sum value for number combination 1-2-3-4-5-6 is 1+2+3+4+5+6=21 so ticket's sum root is *2+1=3*.

Ticket sum of ticket 6-20-23-29-38-42 is 158. Its sum root is then *1+5+8=14 -> 1+4=5*.

See also Sum Root statistics.