digits = [2,4,5,7,9];
sum(perms(digits).*10.^[size(digits,2)-1:-1:0],2);
---
perms(digits)
creates all permutations of digits
10.^[size(digits,2)-1:-1:0]
creates a vector with the relevant orders of magnitude:
ans =
10000 1000 100 10 1
which you can use to give your digits the right positional value:
perms(digits).*10.^[size(digits,2)-1:-1:0]
Now you only need to sum it up row wise:
sum( perms(digits).*10.^[size(digits,2)-1:-1:0] ,2)
