Driving times

Hello everybody, I have a question about the driving times. the 10 hours driving rule left out. How about that, if I drive for example 2 STD and then take a break over 45 min. Then the Digi-Tacho starts to count again. Can I only drive the 4.5 STD or can I drive 4.5 STD again then 45 min break and then in this case still 2.5 STD drive? Do I have to remember the remaining time of the first driving block or is that somehow visible in the Tacho? Hope it is understandable… Domin ic