Texas Instruments TI-73 Explorer User manual

UsingtheTI-73:
AGuideforTeachers
®TableofContents<
Developed by
Cathy Cromar, Stephen Davies, Pamela Patton Giles,
Gary Hanson, Pamela Weber Harris, Rita Janes,
Ellen Johnston, Jane Martain, Linda K. McNay, Melissa Nast,
Louise Nutzman, Aletha Paskett, Claudia Schmitt, and Karen Wilcox
Edited by
Brenda Curry
Design by
Susan Gullord
With contributions by
Eddy Frey, Doug Harnish, Guy Harris,
Gay Riley-Pfund, and Dianna Tidwell

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Using the TI-73: A Guide for Teachers
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About the Development Team
Texas Instruments would like to acknowledge the following individuals who worked as a
team in developing and evaluating these materials.
Cathy Cromar
teacher, Cottonwood Heights Elementary School, Salt Lake City, Utah
Stephen Davies
teacher, Oquirrh Elementary School, West Jordan, Utah
Pamela Patton Giles
K-12 math specialist, Jordan School District, Sandy, Utah
Gary Hanson
teacher, Sprucewood Elementary School, Sandy, Utah
Pamela Weber Harris
teacher, Southwest Texas State University, San Marcos, Texas
Rita Janes
teacher, Newfound Educational Associates, St. John’s, Newfoundland
Ellen Johnston
teacher, Trinity Junior High School, Fort Smith, Arkansas
Jane Martain
teacher, Mountview Elementary School, Salt Lake City, Utah
Linda K. McNay
teacher, Quincy Junior High School, Quincy, Illinois
Melissa Nast
teacher, Arlington, Texas
Louise Nutzman
teacher, Sugar Land Middle School, Sugar Land, Texas
Aletha Paskett
teacher, Indian Hills Middle School, Sandy, Utah
Claudia Schmitt
teacher, Oquirrh Elementary School, West Jordan, Utah
Karen Wilcox
teacher, Columbus, Ohio
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Note: Using calculators other than the TI-73 may produce results different from those described in these materials.
www.ti.com/calc
[email protected]
Copyright © 1998 Texas Instruments Incorporated.
Except for the specific rights granted herein, all rights are reserved.
Printed in the United States of America.

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Using the TI-73: A Guide for Teachers
© 1998 T
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About the Activities
This guide consists of 12 activities designed to be teacher-directed. They are
intended to help develop mathematical concepts while incorporating the
TI-73 as a teaching tool.
Organization
Each activity is self-contained and includes:
♦ The mathematical strands with which the activity is most closely
associated: Number Sense; Patterns, Relations, and Functions;
Measurement and Geometry; or Probability and Statistics
♦ The materials needed to perform the activity
♦ An overview of the mathematical purpose of the activity
♦ The detailed procedure, including step-by-step TI-73 keystrokes
Additionally, most of the activities contain:
♦ A student activity sheet as needed
♦ A teacher black-line master as needed
♦ A section to wrap-up what is being taught
♦ A section to assess what is being taught
♦ A section to extend what is being taught
Conventions Used
♦ Brackets [ ] around a key’s symbol
indicate that the key is a second function
(printed in yellow) on the TI-73.
Example -l
♦ Bold type indicates a calculator display
or format.
Example Done
How To Order Materials
To place an order or request additional information about TI calculators, call
our toll-free number: 1-800-TI-CARES (1-800-842-2737).

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Table of Contents
About the Development TeamAbout the Development Team
iii
About the ActivitiesAbout the Activities
iv
Number Sense
The Cookie Caper
1
Dice Digits
5
How Do You Measure Up?
9
Patterns, Relations, and Functions
Stadium Walls
13
The Twin’s Towers
23
Major Martian Headache
31
Measurement and Geometry
The Dolphin
35
Drip, Drip, Drip
41
Only the Height Has Been Changed
49
Probability and Statistics
Give Me 5!
55
A Foot is a Foot – Or is It?
63
Which Brand is Best?
69
TI-73 IndexTI-73 Index 7979
Activity Content IndexActivity Content Index 8080

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Activity 1
The Cookie Caper
Students learn about equivalent fractions by sharing
their favorite cookies.
Number Sense
♦
equivalent fractions
♦
fractions to decimals
Materials
♦
7cm (2¾ in.) poster board circles for
cookies
♦
copies of fractional circles (provided)
♦
shapes of colored paper to represent
chocolate chips, nuts, raisins etc.
(optional)
♦
glue or glue sticks
♦
scissors
♦
markers or crayons
♦
TI-73 
Setup
Before you begin, you or you and your students do the
following:
♦ For each student, cut a poster board circle with a
diameter of 7cm (2¾ in.) to represent a cookie.
♦ Cut out the fractional circles that are provided and
paste one on the back of each poster board “cookie.”
(Some students will have halves, some thirds, some
fourths, etc.)
♦ Cut shapes of colored paper for raisins, nuts, etc., and
glue them to the front of the cookies, or have students
draw their favorite ingredients on the front of their
cookies.
Activity
Have students perform the steps unless otherwise
indicated.
1. After designing the cookies, turn them over and cut
into the assigned fractional parts pre-pasted on the
back.
2. On a sheet of notebook paper, make a diagram of the
cookie circle and the cuts made to make the assigned
fractional parts.

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Using the TI-73: A Guide for Teachers Number Sense
© 1998 T
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3. Give students a set time period to trade cookie “bites”
(slices) with each other. Tell them they must trade
equal-sized pieces, so they will need to know what
fractional parts are equal to each other.
Example A ½ slice may be traded for two ¼ slices.
At the end of the trade time, each student should still
have a whole cookie, but now it is made of a variety of
cookie ingredients.
4. Discuss the results with your students. Ask:
Why did some have a whole cookie, and some did
not?
What kinds of trades could they have made to end up
with a whole cookie?
5. Use the TI-73 to verify equivalent fraction trades and
to count or add up fractions to see if they equal a
whole cookie.
Example 1 If a student traded ¼ for 3/12, the student
would enter
Y=Q"-t###to =
b#to Done b
[=YZb
➪
If a 1 is displayed on the
right-hand side of the
screen, the 2 fractions are
equivalent. If a 0 is
displayed, they are not
equivalent fractions.
Example 2 If a student traded for ¼, ½, and 3/12,
the student would enter
Y=Q"\Y=Z"
\[=YZb
➪
If a 1 is displayed on the
right-hand side of the
screen, the student knows
the pieces add up to a
whole cookie.

Number Sense Activity 1: The Cookie Caper
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Wrap-up
♦ Have students make a list of the fractions they think
are equivalent to each other.
♦ Have students enter their equivalent fractions into the
TI-73 and change each to a decimal using >
(fraction-to-decimal function). Discuss why these
equivalent fractions also have the same decimal value.
Example Press Y=Q>b.
The display shows .25 as the decimal
equivalent for ¼.
Then enter [=YZ>b.
The display again shows .25 as the
decimal equivalent.
♦ Now have students make a diagram of their final
cookies next to their original diagrams. Have them
label the new fractional parts and decimal amounts.
Extensions
♦ Older students: Change the decimals to percents and
have a pie chart of all three amounts—fractions,
decimals, and percents.
♦ All students: Cut their pieces in half, name the
fractional parts, and trade again for another set time
period. Investigate:
Did they make equivalent trades?
Was it easier this time, or more difficult?
Does the new fractional cookie still add up to a whole
cookie on the TI-73?

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Using the TI-73: A Guide for Teachers Number Sense
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Activity 2
Dice Digits
Students use 4 numbers, any operations, and grouping
symbols to write mathematical expressions that are
equal to each of the numbers 1 through 9.
Number Sense
♦
order of operations
♦
mental math
♦
basic computation
Materials
♦
student activity sheet (provided)
♦
transparency of activity sheet
♦
TI-73 ³
Setup
If your TI-73s have not been used for random number
generation prior to this activity, you and your students
need to store an integer “seed value” to rand in each TI-73.
With each rand execution, the TI-73 generates the same
random-number sequence for a given seed value. The
TI-73 factory-set seed value for rand is 0. To generate a
different random-number sequence, store any non-zero
seed value to rand.
➪
If you do not enter a seed
value, rand uses whatever
value happens to be the
current seed. If there is no
seed, it uses the factory-
set value of 0 .
1. Enter the number you want for your seed value. Have
students use different seed values. (In the example
shown at the right, 1is used.)
2. Now press X1""1b
1""1bb.
(For more information about seed values, refer to the
“1Probability Menu” section in the Math chapter of
the TI-73 Guidebook .)
➪
If you want to restore the
factory-set seed value,
store 0 to rand or reset
the defaults.