Question

write an algorithm to find sum of digit in a numbenumber

Answer 1

Separate the digits and add them together. That's the algorithm. Aside from writing it for you, look up the mod operator ( can be called modulo or modulus ) and integer division for your programming language. Think recursive function.

Answer 2

You could also convert the number into a string, and then use a for loop to add the digits together.

Answer 3

Using the string as an iterable.