123:12+6

It looks like you are trying to add 12 and 6 to the number 123:12. Assuming "123:12" was intended to be a time (123 hours and 12 minutes) and you want to add 6 minutes to it, here's the calculation:

123 hours and 12 minutes + 6 minutes = 123 hours and 18 minutes.

If you meant something else by "123:12 + 6", please provide some more context or clarify your question, so I can assist you accurately.