Source: Cyberchase: “Shari Spotter and the Cosmic Crumpets”
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, Bianca helps a friend get ready for a school bake sale. They are making cupcakes but when they realize that the recipe only makes a dozen cupcakes, decide it is not enough. They want to make double that amount, so they decide to double the recipe, which includes doubling a fraction that results in an improper fraction.
Download and ShareInvestigations/Scott Foresman (2006)
Name That Portion
Investigation 2, Sessions 1-9: pp. 32-62
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: How do you double an amount? Can you double a fraction? How would you double ½? What if you doubled a fraction like ¾? Would you have a number greater than 1? How many different ways could you write that?
Focus: In this video segment, Bianca and her friend have to double 2/3 of a bar of chocolate. Watch how Bianca physically does this with the chocolate. Notice the result when they double two-thirds. What two ways do the girls describe this amount?
Follow Up: How did Bianca and her friend figure out how much 2/3 doubled was? Can you write the resulting amount in two different ways, as a mixed number and as an improper fraction? Draw a picture of the chocolate to show what the resulting amount looks like.
GIRL: Thanks for coming. The Halloween bake sale at school is tomorrow and mom has to work late.
BIANCA: No problem. Let’s get to work.
BIANCA: Looks simple enough. But it only makes twelve cupcakes. Maybe we should double the recipe to sell more.
GIRL: Good idea. I’ll get another bowl.
BIANCA: Oh we don’t need two bowls. We’ll just put in twice the ingredients. Let’s look at the recipe. If it calls for one egg, we’ll put in two. If it calls for one cup of sugar we’ll put in double that. Simple.
GIRL: But it calls for two-thirds of a bar of semi-sweet chocolate. And if we double two-thirds, we get four-thirds. That’s a wacky fraction.
BIANCA: Let me show you. This is a whole bar of chocolate. If I wanted to share it with you, I would break it in half and that would be half for me and half for you. But what if your sister were here?
GIRL: We should break it in thirds, even shares.
BIANCA: Right. So here, break it in thirds.
GIRL: Okay, it’s in thirds.
BIANCA: The original recipe calls for two-thirds of a bar.
GIRL: But we double that.
GIRL: Oh, four thirds is the same as one and a third.
BIANCA: Bingo.
GIRL: What is semi-sweet chocolate anyway?
BIANCA: It’s half sweet and half something else.
BIANCA AND GIRL: They’re ready!
BIANCA. This one came out a little…little.
GIRL: What about icing?
BIANCA: Okay, what’s your favorite song? GIRL: Not I sing, icing.
BIANCA: Oh, fill it to the top with icing. Great idea.
GIRL: Do you want a cupcake? Ok, twenty-five cents…Lots of frosting.
GIRL: Here comes the principal.
PRINCIPAL: Looks like your cupcakes were a big success. Let me buy the last one. What did the mother ghost say to the baby ghost? Stop goblin your food.
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