Raise your hand if you find it harder to teach time in this age of digital clocks and cellphones. Both my hands are raised! Yet analog clocks are part of most state standards. Not only do we need to teach time using analog clocks but combine it with elapsed time. Talk about challenging! Don’t worry I’ve got some ideas for helping kids when finding the elapsed time and ways to practice.
Elapsed Time Definition
Let’s start by talking about what elapsed time is. Elapsed time is the amount of time that passes from the beginning of an event to the end of the event. Sometimes students are asked to find the elapsed time of an event. However, sometimes kids are asked to find the beginning time or the end time. This means kids need practice with all three types of elapsed time problems.
Strategy for Finding Elapsed Time
I use a time number line strategy with mountains and hills and have found this to be the most effective. For example, just say we want to find the elapsed time from 3:15 to 4:35. I ask the kids if we can add an hour to 3:15 without going past the end time. Since we can, we make a mountain to add an hour. This takes us to 4:15.
Next, we find that we can’t add any more hours so we move onto the minutes. Since the last number ends with a 5 we add five more to get to 4:20. Now that the last number is 0 we add 10 to get to 4:30. Then we add 5 more to make it to the end time of 4:35.
The difficult part for some kids is when the start or end time is something like 3:12. In this case, I tell them to figure out how many minutes until you get to a number that ends in 5 or 0. So in this example, we count up to 3:15 which means we add 3 minutes. Then we can proceed to add hours if needed and count by 5’s or 10’s until we reach the end time. Some kids can add bigger chunks of time and that’s ok. I let my students create their time number lines in whatever way works best for them. You can use this same strategy to find the start time. You’d just start at the end of the number timeline and work your way backward.
Finding the Elapsed Time with Task Cards
One we practice finding the elapsed time is with task cards. There are all kinds of ways you can use task cards. I even wrote a post about 3 ways to use task cards here.
When we practice elapsed time with task cards, I like to do a math hunt so that kids are moving. Finding elapsed time can sometimes get boring so adding a little movement makes it a little more engaging.
I set up the cards around the room, in no particular order. (One suggestion is to make doubles so that each student is able to be at one task card by themselves.) I give the kids a recording sheet and have them go around the room and “hunt” the answers down. As the class is going around, working on the elapsed time word problems, I walk around and help individual students.
Elapsed Time Game
To review telling time and elapsed time we play Elapsed Time Race. It’s kind of like the Amazing Race where the kids “travel” to different countries. To set this up in your classroom you’ll need to have areas in the room where you can hang up the information for each country. I use seven chart papers for the seven countries. Put up a picture of the country, a clock, the word problem, and a flag. Then give the kids their passports to collect stamps as they complete each country.
The kids are divided into groups and the groups all begin at a different “country”. They solve the problem and check with the teacher to see if it is correct. If it is, they get to put that country’s stamp in their passport. They race around the different countries to be the first team to reach the last destination! If you don’t want to make it a competition the objective could be to earn a stamp for each country. This is such a fun way to review and the kids love it. If you’d like the game all set up and ready to go, you can get it here.