Counting to the Next Hour:
If the start time is not at a whole number hour, counting to the next hour and then counting on can help students keep track of the time. At the last whole number hour, students can then count on to get to the end time.

How much time has elapsed between 12:20 and 4:15?

Then combine minutes and hours to find the elapsed time: 3 hours and 55 minutes

Counting by Hours:
A variation on that strategy is to count by hours and then count on at the last time to the end time.

How much time has elapsed between 12:20 and 4:15?

Then combine minutes and hours to find the elapsed time: 3 hours and 55 minutes

Try another example from 3:40 to 6:15

Or

How Many In a Minute?
The teacher will time and count how many jumping jacks students can do in one minute. Based on the data from the jumping jack activity, students will calculate how many seconds it took to do one jumping jack and how many jumping jacks they can do in one hour. The purpose of this activity is for students to begin to understand just how long a minute is.

Note: Adjustments to the activity could be tapping finger, drawing circles or other short activities.

How Long is 30 Seconds? A Minute?
To help students understand the length of 30 seconds as opposed to a minute, play the following game. Tell students they are going to estimate how long 30 seconds is. Students need to close their eyes. Tell them that when you say "Go", they will count and when they think 30 seconds is up, they should raise their hands. Say "Go" and time 30 seconds. After 30 seconds is up, say "Stop" and students can open their eyes. Discuss what happened. Some students raised their hands very quickly, while others may not have raised their hands at all, thinking there was still time to go.

Repeat the activity. After several trials, students will become better at estimating the 30 seconds' length of time.

After playing a few times, tell students you are now going to time for one minute. Discuss that 1 minute is twice the length of 30 seconds. Students should consider this when deciding when to raise their hands.

Note: This is a game that can be played while students are standing in line or waiting to use the water fountain. Time increments could be 30 seconds, 1 minute, 2 minutes or any reasonable time interval.

Following a Schedule
Use a schedule such as a movie, bus, train, or plane schedule or make up one. Have students work in partners to make up questions involving start, end, or elapsed time based on the given schedule. Each pair of students can then trade with another pair and answer each others questions.