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# Inventing Negative Numbers

Media Type:
Video

Running Time: 4m 53s
Size: 13.5 MB

or

Source: Cyberchase: “Less Than Zero”

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Collection Credits

### Collection Funded by:

Funding for the VITAL/Ready to Teach collection was secured through the United States Department of Education under the Ready to Teach Program.

In this video segment from Cyberchase the CyberSquad is trying to rescue the Cyberspace Council, which is being held captive by Hacker in a tall building. As Motherboard provides information, the CyberSqaud uses a number line and their knowledge of negative numbers to locate the Council.

Connections

Everyday Math (2004)
Teacher Lesson Guide, pp. 499-501, 530-535, 964
Student Reference, pp. 81-82, 91-92
Math Journal, pp. 229-230
Math Master, pp. 95, 301

Teaching Tips

Here are some Frame, Focus and Follow-up suggestions for using this video in a math lesson.

What is Frame, Focus and Follow-up?

Frame: If you’ve ever looked closely at a thermometer you may have noticed how the numbers on it are arranged in what might be called a number line. Have you ever seen number lines used in other measurement instruments? If the temperature measured on a thermometer starts at five degrees and then it gets seven degrees colder, what is the new temperature?

Focus: In this segment, the CyberSquad receives information from Motherboard about the moves Buzz and Delete are making with the Council. How does the squad finally keep track of these changes and figure out which floor the Council is on?

Follow Up: What floor was the Council on? Did the CyberSquad use addition and subtraction to figure out where the Council was? How? What did they call the numbers below zero? Can you think of another example where you might use negative numbers?

Transcript

MOTHERBOARD: The council has been moved down...three levels.

JACKIE: Down three levels. Got it, Mother B!

MATT: Quick! The stairs!

MOTHERBOARD: They've been blocked ...you will...have to...

DIGIT: Have to what??

INEZ: Have to go outside again!

JACKIE: OK, guys, ready to drop and enter? Down three!

MATT: Just to be sure we do it right, let's doublecheck the numbers as we go down. Down one...

INEZ: Down two...

JACKIE: And down three. Which brings us to level fifteen! Do your stuff, Didge!

INEZ: I can't believe it! We're wrong again!

DIGIT: Maybe the Doc's locator is loco!

MOTHERBOARD: You're not wrong> ...council on the move... We see Motherboard's image in the screen of a nearby treadmill...down eleven...up four...down six...up three...down eight more!

DIGIT:/KIDS: What??!

MATT: Buzz and Delete are out of control.

DIGIT: What else is new?

MOTHERBOARD: The council needs your help! Hurry!

JACKIE: Now what do we do? There's no way we can keep track of these movements!

INEZ: Hold on, maybe there's a shortcut - something we can do so we don't have to go up and down so much. Matt, do you have anything to write on? Thanks. Okay, we've been going up and down floors on our giant ruler, right? Let's make things simpler.

MATT: That looks like a number line!

INEZ: Exactly! We can use this to count out the moves that Motherboard says Buzz and Delete have made and then go directly there!

JACKIE: Let's try it!

INEZ: OK, right now, we're on level fifteen. As Motherboard said, we need to down eleven. Then up four. That puts us at level eight.

JACKIE: Now down six....to level two!

MATT: Now up one, two, three...that puts us at level five.

INEZ: Great! And our last move is down eight levels. To exactly where the council is. One, two, three, four, five...uh-oh!

JACKIE: But that's impossible - we're at zero! We can't go down any further - and we still have to go down three more levels!

DIGIT: I can't take it anymore. My beak is killin' me! Uhh-uhhh-uhhh! Yoikes!

KIDS Digit!!!

DIGIT: Hellllp! Yeow! Whew! Yoikes! Oh! Yeow! Yow! Whew! Ahhh!!! Whoa! Help!!! Helllp!

JACKIE: Hang on, Didge, we're comin!

DIGIT: Whoa!

JACKIE: Gotcha!

DIGIT: Do you see what I see?

JACKIE: What?

DIGIT: That!

JACKIE:/INEZ: Whoa!/Look at that!

MATT: I can't believe it! It looks exactly the same as the purple part of the building up here!

JACKIE: Only it keeps going down. With floors below the ground level.

INEZ: I've got an idea! Let's see what happens if we extend our numberline down...And add more floors below zero...like so!

MATT: One below zero...Two below zero...Three below zero...

JACKIE: Don't you call numbers below zero 'negative' numbers? Why don't we label them so we can tell which is which?

INEZ: Good idea! I'll use the negative sign. Negative one... negative two...

DIGIT: Whoa-whoa-whoa, slow down a second. Negative numbers?

MATT: You know, like when the temperature is ten below zero. Or a parking lot is one below ground level.

DIGIT: Oh, I get it. Negative numbers are less than zero.

INEZ: Let's locate the council! We started - at level fifteen and went down eleven to four then up four to level eight. Right?

MATT: Then down six to level two.

JACKIE: Then up three to level five.

INEZ: And Motherboard's last direction was to go down eight levels. One, two, three, four, five - past zero - six, seven, eight...which brings us three floors below the plaza!

JACKIE: So Motherboard's directions were right!

MATT: Level Negative Three - That's gotta be where the council is! Let's go!

Standards

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