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# Several Short Rails Make More Than A Whole

Resource for Grades 3-6

Media Type:
Video

Running Time: 2m 47s
Size: 7.8 MB

or

Source: Cyberchase: "Mother’s Day"

### 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 is trying to get to the Mother’s Day Harvest on the Madre Bonita Express train. Hacker has ripped out a piece of the train track, however, and Digit must use decimal addition to find a way to repair the track using only the pieces available.

Connections

Everyday Math (2004)
Teacher Lesson Guide, pp. 202-227
Student Reference, pp. 24-35
Math Journal pp. 80-84, 88
Math Master, p. 269

Investigations/Scott Foresman (2006)
Money, Miles, and Large Numbers
Investigation #2, Session 1-4, pp. 30-45

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: Let’s say you had two oranges and cut them both in half. If you took three of those pieces and put them together, how much orange would you have? How would you write that number using whole numbers and fractions? How would you write it using decimals?

Focus: In this segment, Digit is trying to find a piece of track that is the same size as the section of track that Hacker ripped out. Unfortunately there are no pieces of track left that are that exact size. Write down the size of the three pieces Digit uses, and then see if you can add them up to find the total amount of track needed.

Follow Up: What three decimals did the CyberSquad add together to figure out the correct size for the piece of the track? Could they have added fractions to solve their problem? How are fractions and decimals similar? How are they different?

Transcript

DIGIT: Hey, Deci... Deci! Where is that guy? Ah, never mind, I gotta find those rails! Wu-oh, no more short ones! Brain-spark! I’ll just add these numbers like any other numbers - and get one big rail! No problem! Six and two is eight. Eight plus four is...twelve! The answer is twelve! Just pop in the decimal point and... and, wu-oh, where do I put it? Here? Over here? Between here? Boy! I know I gotta put a decimal point somewhere...but where?! Think, Digit...think! Opf! Deci! Am I glad to see you! Hacker messed up the track again - and I need a rail that’s twelve somethings long!

DECI: Twelve somethings??? Where’s your decimal point?

DIGIT: That’s just it...I DON’T KNOW WHERE IT GOES!

DECI: At ease, Didge. Show me the numbers you added. Your addition is first rate! All you need is the right place for the decimal point. Hold out your wings! These are the same length as the rails you need. Point six...point four...point two! Now slide ‘em in here.

DIGIT: Point six...plus point two makes point eight. Plus point four...uh-oh! The point four sticks out past the top!

DECI : Exactly! Because you have more than ten in the tenths place! Try putting in the decimal point two last.

DIGIT: Okay. Point six...plus point four makes...a full tube! Point ten?

DECI: Hold on. You mean ten tenths – one whole tube.

DIGIT: And I’ve still got point two left over! Wait a minute! That gives me one whole...and two tenths!

DECI: Exactly. Perdone.

DIGIT: I don’t have twelve - I’ve got twelve tenths! Which is the same as ten tenths plus two tenths. Or...One point...two! I’m a genius! The point goes between the ones place and the tenths place!

DECI: That is kee-rect, sir! Watch where you put your decimal point - and you’ll always know your place!

DIGIT: So what I need is a one point two rail!

DECI: Affirmative!

Standards

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