Kaprekar’s process - Lycée Bellevue (Alès)

Dattathreya Ramchandra Kaprekar (1905-1986) is an Indian Mathematician.
Kaprekar's process is the iterative process as follows :
-We consider a whole number
-We put the figures of number in decreasing order, which gives us a first whole number N_1 
-We put the figures of number in decreasing order, which gives us a number N_2
-We then make the substraction D = N_1 - N_2
We then reiterate the process on the difference D.

Kaprekar's algorithm is considered as complete when there is always the same quantity of figures in the numbers, by possibly completing them with zeros. Otherwise it is reduced.

We will work on Kaprekar's algorithm on the numbers with 2 figures, then 3, ...