Calculating time differences involves converting each unit into a common measurement. To calculate 0 days, 12 hours, and 55 minutes in the past, you first convert the days into hours. Since 1 day = 24 hours, 0 days equates to 0 hours. Next, add the initial 12 hours to get a total of 12 hours.

Now, convert the 55 minutes to hours by dividing by 60 (since 1 hour = 60 minutes). This gives you approximately 0.92 hours. Finally, add the 12 hours to 0.92 hours to get a total of approximately 12.92 hours in the past.

In future calculations, remember to break down each time unit into a common measurement to accurately determine the time elapsed. This method ensures precision and clarity in time conversions, allowing you to calculate past or future time intervals effectively and avoiding errors in your calculations.