For use withSadako and the Thousand Paper Cranesby Eleanor Coerr.Some friends wanted to make paper cranes for Peace Day. If Mary could make one crane every 2 days, Kim could make one crane every 3 days, and Leo could make one crane every 5 days, how many days would it take for them to complete 1000 cranes?

- Set up a table to display the data.

- Press
Y =key and clear each Y = by pressing theCLEARkey on Y1 = , Y2 = , etc. To move from one Y = to the next, use your down or up arrow keys.First enter rules to display the number of cranes made by each child.

- Type into
Y1 = X/2- Type into
Y2 = X/3- Type into
Y3 = X/5Now, you need to build a rule for finding the total number of cranes made by all of the children.

- Arrow onto
Y4- Press
VARS- Arrow to
Y-VARS- Choose
1: Function- Choose
1: Y1- Press
+- Press
VARS- Arrow to
Y-VARS- Choose
1: Function- Choose
2: Y2- Press
+- Press
VARS- Arrow to
Y-VARS- Choose
1: Function- Choose
3: Y3- You should see Y4 = Y1 + Y2 + Y3
- Press
2nd TblSet- Set
TblMinandat 1/\Tbl

- Modify your table.
Look at your table, especially the tables in the

Y4column. Since you are interested in the number ofcompletedcranes, why are some of the values displayed inY4incorrect?The calculator has a feature which allows you to display the values you need in

Y4. TheiPartfunction returns only the integer part of a value (in our case the whole number part of the value).CLEARthe rule you had inY4and enter the followingY4 = iPart Y1 + iPart Y2 + iPart Y3.

- Arrow into
Y4andCLEARthe rule.- Press
MATH- Arrow right to
NUM- Choose
3: iPart(- Press
VARS- Arrow to
Y-VARS- Choose
1: Function- Choose
1: Y1- Press
)+- Press
MATH- Arrow right to
NUM- Choose
3: iPart(- Press
VARS- Arrow to
Y-VARS- Choose
1: Function- Choose
2: Y2- Press
)+- Press
MATH- Arrow right to
NUM- Choose
3: iPart(- Press
VARS- Arrow to
Y-VARS- Choose
1: Function- Choose
3: Y3- Press
)- You should see Y4 = iPart(Y1) + iPart(Y2) + iPart(Y3)

- Use your table to answer the following questions.

Extension:

- How long would it take Mary working alone to make 1000 cranes?
- How long would it take Kim working alone to make 1000 cranes?
- How long would it take Leo working alone to make 1000 cranes?
- How often do Mary and Kim finish a crane on the same day?
- How often do Mary and Leo finish a crane on the same day?
- How often do Kim and Leo finish a crane on the same day?
- When is the first time all three kids finish a crane on the same day?
- How long will it take the group to make a total of 1000 paper cranes?

- Aman decides to join the group. If he can make one crane every 3 days, how many days would the project now take?
- Design a problem similar to this one so that a group of no more than five friends will complete exactly 1000 paper cranes in 180 days.

Copyright 1997 by Ann Lawrence & Karen Wyatt

Mountain Brook Junior High School

Mountain Brook, AL

wyattk@mtnbrook.k12.al.edu

http://www.ti.com/calc/docs/act/lawrence01.htm

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