This is a hypothetical problem that I would like to explore from the perspective of ML.
I have a number like 45624. If I add up all the digits until I have only one left, I'd do the following:
4 + 5 + 6 + 2 + 4 = 21
2 + 1 = 3
How could I use a neural net or any other technique to model that problem?
IMPORTANT:
The sum of the digits is a modulo 9 operation. So your problem is equivalent toto teach your network to perform a modulo.
Here are some interesting elements of answers.