Source: Cyberchase: "Zeus on the Loose"
Funding for the VITAL/Ready to Teach collection was secured through the United States Department of Education under the Ready to Teach Program.
Three Equal Shares
(Video)
In this video segment from Cyberchase, the CyberSquad must feed Cerberus, the three-headed dog of Greek mythology, in order to escape. The problem is that the dog has three heads and the CyberSquad only has two apples to split between them. It is up to the CyberSquad to figure out how they can divide their apples evenly among Cerberus' three heads.
Download and ShareInvestigations/Scott Foresman (2006)
Arrays & Shares, Session 7 and 8, pp. 35- 41
Different Shapes, Equal Pieces, pp. 2-37
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: Sharing an amount of something equally is not always easy. Can you think of a time when you have had to divide up something to be shared among a group of people? Sometimes when you share things you have to deal with both whole and fractional parts. Can you think of an example when you might have to do this?
Focus: Watch and see how the CyberSquad divides the two apples into equal shares. Notice how their problem-solving process begins with Matt’s statement about what they would do if they only had one apple. Think about how this idea helps them solve the problem. Does the CyberSquad use fractions? Do they use division? How?
Follow Up: How did the CyberSquad go about sharing the apples among the three heads in a fair way? The CyberSquad divided the apples up by cutting them and giving each head an equal amount. While they did this they talked about fractions. How are the concepts of fractions and dividing related? What if the CyberSquad needed to have smaller pieces for the dog to chew more easily? How would they have divided the apples up evenly?
DIGIT: D-d-d-d-dogs! M-m-m-m-monster!
INEZ: I take it back. We’re staying. Unless you help us get rid of that carnivorous canine.
ATLAS: Feed him apples from that tree and you’ll have time to get away.
ATLAS: But feed each head exactly the same amount - or they’ll eat you.
MATT: But we only have two apples!
INEZ: So, how do we share two apples equally with three heads?
KIDS: YIKES!
ATLAS: Great! It’s not enough I’m holding up the sky - now I have a three-headed dog on my foot!
MATT: (calling up) Up the tree! Guys, hurry!
JACKIE: Okay, here’s the plan. We slice the two apples into equal shares - just like we did the wreath.
INEZ: So how many pieces do we need?
MATT: Well, if we only had one apple, we’d cut it into three equal pieces. One for each head.
INEZ: Yeah, but we have two apples!
JACKIE: Well, we could cut each apple into three equal pieces.
INEZ: I suppose that’s one way to look at it.
DIGIT: Just cut the apples, will’ya?
DIGIT: Yoikes! Step lively, kiddlies!
MATT: We better double check this idea on the Skwak Pad to make sure the dog just eats the apples - and not us.
JACKIE: Okay, here’s what we have: two apples...And here’s who we need to share them with: three heads.
DIGIT (POINTING TO SKWAK PAD): Uh...you think you could put a line between ‘em so I... don’t get confused?
JACKIE: No problem!
MATT: Cool! It’s like a fraction! Two apples over three heads.
INEZ: It is a fraction!
DIGIT: It is?
INEZ: Sure! The top number shows you what you’ve got to share, and the bottom number shows you how many ways you have to share it.
INEZ: Look! We divide the first apple into three parts...And each head gets one-third. The apples break into three equal parts, each part sliding down above each head.
JACKIE: I see where you’re going. Then we split the second apple into thirds and give each head another third!
MATT: That’s it! The number two-thirds is the answer to our sharing problem. Each head gets two-thirds of an apple! s!
Loading Standards
Connections
Print Connections