Time calculator

How i calculate

(A) Initial time: 13:40:12
(B) Final time: 13:52:50

Interval time is: (B-A) seconds

I have problem in understand Date H/M/S in MIT

You can use the duration blocks in the clock timer palette
or convert the time instants to milliseconds and do the maths
Date formats: https://docs.oracle.com/javase/7/docs/api/java/text/SimpleDateFormat.html