📊Math G3 L7.5 🤔Explore A - Elapsed Time to the Minute

For this lesson you will need the open number line mat and the student clock found in the lesson materials.

Voice Explanation

Part 1

1.  What do you know?

• Started a movie at 8:45 pm
• Didn't go to be until 12:13 in the morning

2.  What can you do?

• Find out how long from 8:45 to midnight
• Find out from midnight to 12:13

3.  What could be asked of you?

• How long after the movie did they go to bed?

Voice Explanation

To help us solve this problem we are going to use a t-chart.

The change in time column is how much is being added or subtracted--the interval between the times listed in the 1st column (or the jumps).

Let's start at 8:45.

What is one hour from 8:45?

• 9:45
• Write 9:45 in the "time" column and +1 hour in the "change in time" column.

What is one hour from 9:45?

• 10:45
• Write 10:45 in the "time" column and +1 hour in the "change in time" column.

What is one hour from 10:45?

• 11:45
• Write 11:45 in the "time" column and +1 hour in the "change in time" column.

(Voice explanation)

Can we go any further using whole hour jumps without going past 12:13?

• No

Let's go to 12:00.

• 12:00 is 15 minutes from 11:45
• Write 12:00 in the "time column" and +15 minutes in the "change in time" column.

How far is it from 12:00 to 12:13?

• We could jump 15 minutes to 12:15 and then go back 2 minutes.
• We could jump 10 minutes to 12:10 and then go 3 more minutes

(Voice explanation)

What is the total elapsed time?