Texas Instruments TI-15 User manual

Front
TI-15
A Guide for Teachers

TI.15:
A Guide for Teachers
Developed by
Texas Instruments Incorporated
Activities developed by
Jane Schielack

About the Author
Jane Schielack is an Associate Professor of Mathematics Education in the Department of Mathematics at
Texas A&M University. She developed the
Activities section and assisted in evaluating the appropriateness of
the examples in the
How to Use the TI-15 section of this guide.
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Copyright © 2000 Texas Instruments Incorporated.
Except for the specific rights granted herein, all rights are reserved.
Printed in the United States of America.
Automatic Power Down, APD, and EOS are trademarks of Texas Instruments Incorporated.

© 2000 TEXAS INSTRUMENTS INCORPORATED TI-15:A Guide for Teachers iii
Table of Contents 
CHAPTER PAGE
About the Teacher Guide ........................... v
About the TI-15 ........................................... vi
Activities................................................ 1
Patterns in Percent ....................................2
The ªKey
Fraction Forms ........................................... 6
Auto and Manual Mode
Comparing Costs........................................ 11
Division with quotient/remainder,
fraction, or decimal result
Number Shorthand ...................................15
Scientific Notation
Related Procedures..................................20
Constant operations
In the Range............................................... 24
Rounding
The Value of Place Value ..........................29
Place value
What’s the Problem?................................34
Number sentences, Problem solving
How to Use the TI.15 ....................... 38
1 Display, Scrolling, Order of
Operations, Parentheses..................39
2 Clearing and Correcting..................... 42
3 Mode Menus.........................................45
4 Basic Operations................................48
5 Constant Operations.........................55
6 Whole Numbers and Decimals..........63
7 Memory .................................................68
8 Fractions ............................................... 71
9 Percent................................................. 80
10 Pi.............................................................84
11 Powers and Square Roots ............... 88
CHAPTER PAGE
How to Use the TI-15 (continued)
12 Problem Solving: Auto Mode............ 94
13 Problem Solving: Manual Mode ......100
14 Place Value..........................................106
Appendix A ................................................A-1
Quick Reference to Keys
Appendix B.................................................B-1
Display Indicators
Appendix C ............................................... C-1
Error Messages
Appendix D ...............................................D-1
Support, Service, and Warranty

© 2000 TEXAS INSTRUMENTS INCORPORATED TI-15: A Guide for Teachers iv
About the Teacher Guide 
How the Teacher Guide is Organized
This guide consists of two sections: Activities
and How to Use the TI-15 . The Activities
section is a collection of activities for
integrating the TI-15 into mathematics
instruction.
How To Use the TI-15 is designed
to help you teach students how to use the
calculator.
Activities
The activities are designed to be teacher-
directed. They are intended to help develop
mathematical concepts while incorporating
the TI-15 as a teaching tool. Each activity is
self-contained and includes the following:
• An overview of the mathematical purpose
of the activity.
• The mathematical concepts being
developed.
• The materials needed to perform the
activity.
• A student activity sheet.
How to Use the TI.15
This section contains examples on
transparency masters. Chapters are
numbered and include the following:
• An introductory page describing the
calculator keys presented in the examples,
the location of those keys on the TI-15, and
any pertinent notes about their functions.
• Transparency masters following the
introductory page provide examples of
practical applications of the key(s) being
discussed. The key(s) being discussed are
shown in black on an illustration of the
TI-15 keyboard.
Things to Keep in Mind
• While many of the examples on the
transparency masters may be used to
develop mathematical concepts, they
were not designed specifically for that
purpose.
• For maximum flexibility, each example and
activity is independent of the others.
Select the transparency master that
emphasizes the key your students need
to use to develop the mathematical
concepts you are teaching. Select an
appropriate activity for the
mathematical concept you are teaching.
• If an example does not seem
appropriate for your curriculum or
grade level, use it to teach the function
of a key (or keys), and then provide
relevant examples of your own.
• To ensure that everyone starts at the
same point, have students reset the
calculator by pressing −and ”
simultaneously or by pressing ‡,
selecting RESET, selecting Y(yes), and
then pressing <.
How to Order Additional Teacher Guides
To place an order or to request additional
information about Texas Instruments (TI)
calculators, call our toll-free number:
1-800-TI-CARES (1-800-842-2737)
Or use our e-mail address:
[email protected]
Or visit the TI calculator home page:
http://www.ti.com/calc

© 2000 TEXAS INSTRUMENTS INCORPORATED TI-15: A Guide for Teachers v
About the TI.15
Two-Line Display
The first line displays an entry of up to 11
characters. Entries begin on the top left. If
the entry will not fit on the first line, it will
wrap to the second line. When space permits,
both the entry and the result will appear on
the first line.
The second line displays up to 11 characters. If
the entry is too long to fit on the first line, it
will wrap to the second line. If both entry and
result will not fit on the first line, the result is
displayed right-justified on the second line.
Results longer than 10 digits are displayed in
scientific notation.
If an entry will not fit on two lines, it will
continue to wrap; you can view the beginning
of the entry by scrolling up. In this case, only
the result will appear when you press ®.
Display Indicators
Refer to Appendix B for a list of the display
indicators.
Error Messages
Refer to Appendix C for a listing of the error
messages.
Order of Operations
The TI-15 uses the Equation Operating
System (EOSé) to evaluate expressions. The
operation priorities are listed on the
transparency master in Chapter 1,
Display,
Scrolling, Order of Operations, and Parentheses
.
Because operations inside parentheses are
performed first, you can use Xor Yto
change the order of operations and, therefore,
change the result.
Menus
Two keys on the TI-15 display menus: ‡
and ¢.
Press $or #to move down or up through
the menu list. Press !or "to move the
cursor and underline a menu item. To return
to the previous screen without selecting the
item, press ”. To select a menu item, press
®while the item is underlined.
Previous Entries #$
After an expression is evaluated, use #
and $to scroll through previous entries
and results, which are stored in the TI-15
history.
Problem Solving (‹)
The Problem Solving tool has three features
that students can use to challenge
themselves with basic math operations or
place value.
Problem Solving (Auto Mode) provides a set
of electronic exercises to challenge the
student’s skills in addition, subtraction,
multiplication, and division. Students can
select mode, level of difficulty, and type of
operation.
Problem Solving (Manual Mode) lets
students compose their own problems,
which may include missing elements or
inequalities.
Problem Solving (Place Value) lets students
display the place value of a specific digit, or
display the number of ones, tens, hundreds,
thousands, tenths, hundredths, or
thousandths in a given number.

© 2000 TEXAS INSTRUMENTS INCORPORATED TI-15: A Guide for Teachers vi
About the TI.15 (Continued)
Resetting the TI.15
Pressing −and ”simultaneously or
pressing ‡, selecting RESET, selecting Y
(yes), and then pressing ®resets the
calculator.
Resetting the calculator:
• Returns settings to their defaults:
Standard notation (floating decimal),
mixed numbers, manual simplification,
Problem Solving Auto mode, and Difficulty
Level 1 (addition) in Problem Solving.
• Clears pending operations, entries in
history, and constants (stored
operations).
Automatic Power DownTM (APDTM)
If the TI-15 remains inactive for about
5 minutes, Automatic Power Down (APD)
turns it off automatically. Press −after
APD. The display, pending operations,
settings, and memory are retained.

© 2000 TEXAS INSTRUMENTS INCORPORATED TI-15: A Guide for Teachers 1
Patterns in Percent 2
Fraction Forms 6
Comparing Costs 11
Number Shorthand 15
Related Procedures 20
In the Range 24
The Value of Place Value 29
What’s the Problem? 34
Activities

© 2000 TEXAS INSTRUMENTS INCORPORATED TI-15: A Guide for Teachers 2
Patterns in Percent Grades 4 - 6
Overview
Students will use the ªkey to collect data about
percentages of a given number. They will organize the
data and look for patterns in percents. (For
example, 10% of 20 is twice as much as 5% of 20.)
Math Concepts
• multiplication
• equivalent
fractions,
decimals, and
percents
Materials
• TI-15
• pencil
• student
activity
(page 4)
Introduction
1. After students use manipulatives to develop the
meaning of percent (1% = 1 part out of 100 parts),
have them explore what happens when they
press ªon the calculator.
2. Present the following scenario to students:
Metropolis East (M.E.) and Metropolis West
(M.W.) are neighboring cities. The sales tax in
M.E. is 10%, but the sales tax in M.W. is only
5%. Collect data and display your results for
each percent in a table to compare the amounts
of money you would pay for tax on various
items in each city.
3. Have students make conjectures about percent
based on the patterns they observe. Students can
then use manipulatives to verify their
conjectures.
Examples:
• Students may observe that for every item, 10%
of its price is twice as much as 5% of its price.
• Students may observe that it is easy to
estimate 10% of a whole number by using
place value and looking at the digits to the
right of the ones place.
Collecting and Organizing Data
To guide students in organizing their data to bring
out patterns, ask questions such as:
•
How could you organize your data to compare
the 5% tax rate to the 10% tax rate?
•
Why would it be useful to keep 5% in the left-
hand column of one table all the way down and
just change the total quantity?
³When a student enters
a 6 ª, the TI-15
displays 6%. Then,
when the student
presses ®, the
display changes to
6%= 0.06 to show that
6% is another way to
write 0.06 or 6/100.
³You will need to show
students how to use
multiplication on the
TI-15 to express the
percent of a given
quantity. For example,
to show 10% of $20:
1. Enter 10.
2. Press ªV.
3. Enter 20; press ®.
Students can verify the
calculator display of 2
by using manipulatives
to show 10% of $20 =
$2.

© 2000 TEXAS INSTRUMENTS INCORPORATED TI-15: A Guide for Teachers 3
Patterns in Percent (Continued)
•
How can you make a similar table for 10% to
compare your data?
•
What do you think would happen if you order
the total quantity amounts from least to
greatest?
•
How else might you organize your data to
compare the two tax rates and find patterns in
the percents?
Analyzing Data and Drawing Conclusions
To focus students’ attention on looking for patterns
in their data, ask questions such as:
•
How are the percentages (amounts of tax) in
your 5% table like the amounts in the 10% table?
•
How does 5% of a $20 item compare to 5% of a
$10 item?
•
How does 10% of a $20 item compare to 10% of
a $10 item?
•
How does 10% of the cost of an item compare to
the total cost of the item?
•
What conjectures can you make about finding
10% of a number?
•
What conjectures can you make about finding
5% of a number?
•
How can you use manipulatives to test your
conjectures?
Continuing the Investigation
Students can create other percent scenarios to
investigate patterns in percents. For example, ask
students:
•
What happens if you increase the sales tax by
one percentage point each day?
•
How does the tax on a $20 item change each
day?
•
How does the tax on a $40 item change each
day?
•
How do the taxes on the 2 items compare?