One Atta Time Flash Cards Distance Learning Create New Sheet Select a Worksheet > Version 1 Version 2 Version 3 Version 4 Version 5 Version 6 Version 7 Version 8 Version 9 Version 10 Grab 'em All Time Only 3md1 Find the start time when you know the end time and how long something lasted.Use subtraction to take away elapsed time from a given time.Keep track of time when crossing from one hour to the previous hour.