You could do this in two ways, you could either subtract immediately or convert the time given in hours into minutes STEP 1: 8:10 - 7:40 which will give 0:30 STEP 2: 8 hours 10 minutes into minutes is (8 * 60) +10 = 490 minutes 7 hours 40 minutes into minutes is (7*40) + 40 = 460 minutes 490 - 460 = 30minutes
