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# Finding the Right Crystal

Resource for Grades 4-8

Media Type:
Video

Running Time: 1m 41s
Size: 4.7 MB

or

Source: Cyberchase: “A Piece of the Action”

### 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, the CyberSquad has to find a crystal that is between 65% and 85% orange in order to power up their escape from the Hacker. The CyberSquad manages to describe each crystal's colors using fractions, but then they must convert the fractions into percentages in order to easily compare the amounts.

Connections

Everyday Math (2004)
Teacher Lesson Guide, pp. 305-310, 316-326
Student Reference, pp. 47-54, 90, 238
Math Journal, pp. 149-151, 155-156
Math Master, pp. 66, 75, 155, 272, 274

Investigations/Scott Foresman (2006)
Name That Portion
Investigation 1, Sessions 1-7, pp. 2-31

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 got 80 out of 100 questions correct on a test, what would your percentage of correct answers be? What fraction describes the number of questions you got correct? Are fractions and percentages related? How?

Focus: As you watch this segment, notice how the CyberSquad figures out what fraction of each crystal is orange. Write down these fractions. Then watch as these fractions are converted into percentages. How is this done?

Follow Up: How was multiplication used to help convert the fractions into percentages? What is it about the denominators of the fractions that is important when comparing the fractions and when converting them to percentages? Could you convert 3/10 into a percentage?

Transcript

MATT: Remember what the sign said? The crystal has to be between sixty-five percent and eight-five percent orange - or it won't work!

DIGIT: You're right! We gotta find out what percent of these crystals is orange!

MATT: Let's do what we did before! Count the stripes to get the fraction of each crystal that's orange.

INEZ: Yeah, then we can turn the fraction into a percentage - like we did with the scores!

JACKIE: This one is one half orange...

INEZ: This one is three fifths and the last one is three/fourths.

ROXY: Now we gotta turn those fractions into fur-scents, I-I mean per-cents...right?

INEZ: Yep...parts of a hundred. The first is easy. One half is the same as fifty over a hundred...or fifty percent!

MATT: And three over five is the same as how many out of 100? Let's see 3 over 5 is 6 over 10...And 6 over 10 is sixty over 100 or 60 percent.

DIGIT: The last one is three over four. Which is, uh...what part of a hundred?

INEZ: Well 4 times 25 is 100...and 3 times 25 is 75. So that's 75 over a 100, which is the same as 75 percent.

DIGIT: Percents really help when you have to compare different fractions.

MATT: They sure do! And only one of these crystals is between sixty-five and eight-five percent orange...the seventy-five percenter!

Standards

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