Question

find the sum of digits of a number until a single digit is occurred.

Answer 1

Okay, but, what is the number????????????????

Answer 2

if n <10

digit sum is n

or

digit sum (n)= sum of digit sum (n)

ex:1.)1+2+3+4=10

1+0=1

2.) 5+6+7+8=26

2+6=8

this answer may help u