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# Balancing Equations with Multiple Terms

Media Type:
Video

Running Time: 3m 15s
Size: 8.9 MB

or

Source: Cyberchase: “A Battle of Equals”

### Collection Developed by:

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, Inez and Digit are attempting to gain access to a machine in order to save Sensible Flats from disaster. First, they must balance a scale to get the correct numeric access code. In order to do that they have to balance a scale using four weights on each side. They soon learn that adding or removing the same weight from each side does not upset the balance of the scale.

Connections

Everyday Math (2004)
Teacher Lesson Guide: pp. 189-193
Teacher Reference Manual: pp. 49, 277-283
Student Reference Book: pp. 207-213

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 were helping younger children to play on a seesaw and there were three children of approximately equal weight on one side and only one child on the other side, how many more children would you put on the lighter side in order to get it to balance? What if one side had three children and the other side had four children? What would you do then to make the seesaw balance if there were no other children around?

Focus: As you watch, notice which numbers Inez and Digit put on each side of the scale to make it balance. When Inez realizes there are more weights than there are numbers on the machine, what does she do? How does she keep the scale balanced?

Follow Up: What numbers did Inez and Digit use on each side of the balance? Can you think of four numbers to put on each side of the scale that would make it balance? What if one of the numbers was a seven and you had to remove it from one side? What would you remove from the other side to keep the scale balanced?

Transcript

INEZ: Those poor bunnies!

INEZ: We have to save them, Didge! We have to!

DIGIT: Awright, awright, we will! Yoikes!Look at all these places we gotta fill in.

INEZ: And look at all these weights! If we have to find a balance using all of them - it'll take forever!

DIGIT: Well, we gotta start somewhere. Here's a six.

INEZ: Here's another six!

INEZ: Here's a two. And another two!

DIGIT: Hey, whadda you know?! When you add the same weight to each side, it still balances! I think it's sinkin in!

INEZ: We did it! We balanced the scale using all the weights! Let's put in the numbers and save those bunnies!

INEZ: Uh oh!

DIGIT: What uh oh? I don't like uh ohs!

INEZ: There are only four places on each side to put numbers - and we have five weights on each side! One too many on each side of the scale!

DIGIT: Don't tell me we have to start over!

INEZ: Oh, and we're running out of time! Those cute little bunnies can't dodge the cyberstatic forever!

DIGIT: Nezzie! Get a grip!

INEZ: You're right, Didge. Maybe we don't have to start over!

DIGIT: Do you really think better that way?

INEZ: Which way? Okay, what do we know? We know when we add the same amount to each side of a balanced scale, it still balances.

DIGIT: So maybe if we take away the same amount from each side - it'll stay in balance too!

INEZ: Of course! The new totals on each side will still match each other. We just have to figure out which weights Hacker didn't use, and remove them.

DIGIT: No problemo! The old beakeroo can smell The Hacker a mile away! Yech! The Hacker touched this one for sure. Phoof! This one too! And this one.

DIGIT: But not this one! The 4 weight is clean!

INEZ: Let's see if you're right. We'll take a 4 from each side...

DIGIT: Easy...easy...beauteeful! We're still balanced.

INEZ: That leaves us with a six - a two - a five - and a three on each side! Let's hope that's right.

INEZ: The total on the left side equals the total on the right side.

VOICE: Security access permitted!

Standards

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