Review time intervals to ensure that students have a firm understanding of these fundamentals. Count by 5s, pointing to each number of the clock. Point out the individual minute markings between each number on the clock, so students understand that one complete rotation around the clock with the minute hand is 60 minutes. Test children's ability to tell time by setting the clock to various times and quizzing them. Make sure students understand telling time down to 5-minute intervals before advancing into elapsed time.
Talk about how much time it takes for students to perform certain activities. For example, ask students whether it takes them two minutes or two hours to brush their teeth. Give students choices between two time periods for a variety of activities, so students begin to think about how much time passes as they perform activities throughout the day.
Figure out simple time elapse problems aloud with the students. Give a time that an activity starts and ends and ask children to figure out how much time elapses from the start to the finish of the activity. For example, if a swim lesson starts at 10:00 and ends at 11:30, demonstrate the time elapse with the clock by starting the time at 10:00 and moving the minute hand until the time reads 11:30. Count by 5s to reach 90 minutes. Help students see that 90 minutes is equivalent to 1 1/2 hours or 1 hour and 30 minutes.
Write time-elapse problems on the board, and work through the process to solve them together. Make the difficulty level of the problems steadily more difficult, with the final problem something more complex, such as: "Annie reads between 8:00 and 8:45 each evening on Monday through Friday. She does not read at all on Saturday. On Sunday, Annie reads between 2:00 and 4:00. How long does Annie spend reading this week?" Help students count the minutes between 8:00 and 8:45 and multiply this by five. Help students count the minutes between 2:00 and 4:00. Show students how to add the total minutes -- 345 minutes. Show children how to convert this to hours by dividing 345 / 60 = 5.75. Annie read 5 hours and 45 minutes.