list digit into number

[deanhystad]

Play the part of the computer to see why your program doesn't work

Output:
digits = [1, 2, 12, 123]
e1   result  result*10  result*10+e1
1    0       0          1
2    1       10         12
12   12      120        132
123  132     1320       1443

For two and 3 digit numbers you are not "shifting" result enough. If e1 has 2 digits you need to multiply result by 100. If e3 has 3 digits you need to multiply result by 1000.

This assumes that the problem must be solved mathematically instead of just converting everything to str and concatenating (and maybe converting the result tack to an int).