digit sum

[jacks]

Sum of 5 or 4 digit number which can be formed by the digits 0,1,2,3,4

[pabloN]

Spoiler (click para mostrar u ocultar)

First, we will sum all four digit numbers that you can make with . The first ones (from to ) are:

Looking at the table above, it is easy to note that:



Thus the sum of all possible four digit numbers is:



Proceed in a similar way to calculate the sum of the five digit numbers.