Digital Roots:
The digital root of a number is obtained by repeatedly adding its digits until only one digit remains. 
     
Example 1 Example 2
\(489710\)
 \(4 + 8 + 9 + 7 + 1 + 0\)
 \(= 29\)
 \(2 + 9\)
 \(= 11\)
 \(1 + 1\)
 \(= 2\)
 Digital Root \(= 2\)
\(357\)
 \(3 + 5 + 7\)
 \(= 15\)
 \(1 + 5\)
 \(= 6\)
 Digital Root \(= 6\)