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How Many Rails for the Detour?

Media Type:
Video

Running Time: 2m 33s
Size: 7.6 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 must build a rail line to get around the mountain to transport flowers gathered from Thornium Mountain. To do this they must complete decimal addition to figure out how long to make the new rail line. After looking at their sum, the CyberSquad believe that something is not quite right. They realize they did not line up the decimal points when they added the numbers, so they fix their mistake and add up the numbers again.

Connections

Everyday Math (2004)
Teacher Lesson Guide,
pp. 79-84, pp. 286-304
Student Reference, pp. 26-30
Math Journal, p. 32
Math Master, p. 228

Investigations/Scott Foresman (2006)
Name That Part,
Investigation 1, Session 4: pp. 2--3
Between Never and Always
Investigation 1, Sessions 1 and 2, pp. 4-18
Measurement Benchmark
Investigation 1, pp. 25-37

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: When we talk about amounts or distances that are less than one we can use fractions or we can use decimals. Both describe quantities less than a whole. Have you ever had to add decimals together? How do you begin? Is the placement of the decimal point important?

Focus: As you watch this segment, you will see that the CyberSquad has to add three numbers. Notice what kind of numbers they are and how one of those numbers is different from the other two. Then watch as Jackie attempts to add them. She makes one mistake. See if you can tell what it is.

Follow Up: What was the mistake that Jackie made when she tried to add the two decimal numbers and the whole number? When decimal numbers are added, what is important to do with the decimal point? When you are adding decimals to whole numbers, what should you do about decimal points in that situation?

Transcript

JACKIE: That's it. We've got tons of flowers. We're out of here.

MATT: Back to the tunnel! Are the tracks clear?

DIGIT: This cement is too hard!

JACKIE: Oh, man, now there's no way to get the flowers to the portal!

MATT: We let Motherboard down. Hacker won.

INEZ: Not yet, guys! We can go around the mountain!

JACKIE: But there's no rail for the train!

MATT: So? We'll lay down a new one - and connect it to the old one. We can do that!

DIGIT: Yeah! How much rail do we need?

INEZ: According to this, it's one point five rails from here to the next signal.

JACKIE: One point five...got it!

MATT: One point eight from here to the bridge.

INEZ: Plus two full rails to get across the bridge. Hmpf! That's all we need!

JACKIE: I'll add it up. Five and eight is thirteen plus two is fifteen...carry my one...for a grand total of...Three point five rails!

INEZ/MATT/DIGIT: Huh???

MATT: That can't be right, Jax.

INEZ: It has to be more! The sign said we need rails that are one point five long plus one point eight long and another that's two rails long.

MATT: Yeah. That's a least four whole rails.

DIGIT: May I? Remember, you have to add the same size pieces. Tens to tens and ones to ones.

JACKIE: Right.

DIGIT: This two is a whole number so it needs to be in the ones place. And where is the ones place? Over here - left of the tenths place. That's where. And it's not just two - it's two point zero. We write a zero here - 'cause there are no tenths. So, eight and five is thirteen. Carry my one. Now two plus one plus one plus the one we carried over is five... for a real total of...Five point three! To keep your places straight - you gotta keep your decimals straight!

JACKIE: Sorry, guys. I put the two in the wrong place.

MATT: Didge, you're a wonder!

DIGIT: I know that!

Standards

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