📊Math G3 L7.4 🤔Explore B - Using an Open Number Line

Part 1

(Voice explanation)

1.  What do you know?

• The start time is 6:30.  The end time is 7:20

2.  What can you do?

• Determine the elapsed time.

3.  What could be asked of you?

• To determine how long the play lasts (the elapsed time).

Let's use a clock to help us as well as a number line.

(Voice explanation)

a) Is it possible to jump an hour?

What is an hour from 6:30?

• 7:30
• This is beyond our end time.  We would need to go back the extra amount.

(Voice explanation)

This shows 1 hour minus 10 minutes.

1 hour is 60 minutes.

60 minutes - 10 minutes = 50 minutes.

The play lasts 50 minutes.

(Voice explanation)

b) What if we don't jump the hour?

What if we go to the next hour of 7?  How long is that?  

(Voice explanation)

• 30 minutes

How many more minutes to 7:20?

(Voice explanation)

• 20 minutes.

How long?

• 30 minutes + 20 minutes = 50 minutes.