Texas Instruments TI-15 - User Manual

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TIN15
Calculator and Arithmetic Trainer
Copyright  1999 Texas Instruments Incorporated
General Information
The TI-15 has two power sources-battery and solar. It
operates in well-lit areas using solar cell, and it operates in
other light settings on battery.
Examples: See the Examples page for representative
problems and keystroke sequences that demonstrate many
of the TI-15’s functions and capabilities. Before starting
each problem set, reset the calculator by pressing
− and
” simultaneously to help ensure that your displays are
the same as those shown in the examples. In Problem
Solving Auto mode, however, displays will vary from those
shown, because these problems are random.
Basic Operations
To turn the TI-15 on, press −.
If the calculator is on, press
− to turn it off.
APD™ (Automatic Power Down™) turns off the TI-15
automatically if no key is pressed for about 5 minutes.
Press
− after APD to power up again; the display,
pending operations, settings, and memory are retained.
Display and Scrolling " ! # $
The TI-15 has a two-line display; each line has room for 11
characters. Entries that do not fit on the first line wrap to
the second, and then scroll when the second line is filled.
Exception: When computing fractions, the TI-15 displays
only one line, which scrolls when a problem exceeds the
capacity of the line.
Entries can be up to 88 characters. Exceptions: In Stored
Operations, the limit is 44 characters. In ‹ Man mode,
entries do not wrap; entries cannot exceed 11 characters.
When a result exceeds the capacity of the screen, it is
displayed in scientific notation. However, if the result is
greater than 10^99 or less than 10^L99, you will get an
overflow error or underflow error, respectively.
Scroll with ", !, #, and $.
¦ Press " and ! to scroll through entries or to move the
underscore within a menu list.
¦ Press # and $ to scroll through history or, within a
menu, to move to the next level of menu lists.
Clearing, Correcting and Resetting ” w
w Deletes the character to the left of the
cursor. In fractions, clears from right
bottom to left top.
” Clears display and error condition.
(Does not clear value from memory.)
|| Clears value from memory.
− and ”
To reset, hold down − and ”
simultaneously for a few seconds and
release. MEM CLEARED displays.
This completely clears the calculator
and restores all default settings. You
can also reset using the Mode menu
(see below).
Display Indicators
Indicator Definition
‹
Calculator is in Problem Solving mode.
ƒ
Calculator is in Place Value mode.
Fix
Calculator is rounding results.
4M
z has been pressed.
M
A value other than zero is in memory.
Op1, Op2
Stored operation function is active.
Auto
In calculator mode, Auto simplification of
fractions is active. In ‹, Problem Solving
function is in Auto mode.
I Integer division function is active (appears
only when cursor is over the division sign).
n
d
P
Results of division will be displayed in
fraction format.
N
D
"
n
d
The fractional result can be simplified.
º »
More entry history or menus are available.
Press # or $ to access.
! "
An entry or menu extends beyond the
capacity of the screen. Press ! or " to
scroll.
Mode Setting Menus ‡ ¢ ‹ Œ
Key Menu Choices Displayed
‡
‡$
‡$$
‡$$$
. n/d (Decimal or fraction display)
+1 ? (Show or hide in Op)
OP1 OP2 (Clear stored Op)
N Y (Select or reject Reset)
¢
¢$
U n/d n/d (Select format of fractions)
Man Auto (Simplification procedure)
‹‡
Auto Man (Automatic or Manual)
‹‡$
1 2 3 (Level of difficulty)
‹‡$$
‹‡"®$
+ - Q P ? (Type of operation)
11-. -1- (Place Value function)
Press ! or " to underline a menu item. To select the
underlined item, press ®. To exit, press
‡.
Order of Operations
The TI-15 uses the Equation Operating System (EOSé) to
evaluate expressions.
1st Expressions inside parentheses.
2nd Functions that need a ) and precede the argument.
3rd Fractions.
4th Exponentiation (^) and roots (‡).
5th Negation (L).
6th Multiplication, implied multiplication, division.
7th Addition and subtraction.
8th Conversions (U n/d/n/d, F/D, 4%).
9th ® completes all operations.
Basic Arithmetic T U V W r « ®
q, h, i, j, k,
l, m, n, o, p
Enters numerals 0 through 9.
T, U, V, W Adds, subtracts, multiplies, divides.
r Inserts decimal point.
M Enters a negative sign. (Does not
act as an operator.)
X, Y Opens, closes a parenthetical
expression.
® Completes all operations.
Integer Division £
When you divide a positive whole number by a positive
whole number with £, the result is displayed in the form
Q r R, where Q is the quotient and R is the remainder.
If you use the result of integer division in a subsequent
calculation, the TI-15 uses only the quotient; the remainder
is dropped.
Fractions  ¥  ¢ ¦ ¤ §
Ÿ
Press  after entering a number to designate the
numerator of a fraction.
Press ¥ after entering a number to designate the
denominator of a fraction.
Both numerator and denominator must be integers. If you
enter a denominator greater than 1000, or if a calculation
yields a denominator greater than 1000, the TI-15 displays
results in decimal format.
You can input either the numerator or the denominator first.
 separates the whole number from the fraction in a
mixed number.
¢ displays a menu that lets you specify how fraction
results are displayed.
¦ U n/d (default) displays results as mixed numbers.
¦ n/d displays results as simple (improper) fractions.
¢$ displays a menu that lets you specify the
simplification method.
¦ Man (default) requires manual simplification of fractions.
¦ Auto automatically reduces fraction results to lowest
terms.
N/D"n/d indicates that fraction results can be simplified.
¤ enables you to simplify a fraction manually.
§ displays the factor that was used to simplify a fraction
in your last manual simplification step. Press § again to
restore the fraction to the screen.
¦ converts a mixed number to an improper fraction or
an improper fraction to a mixed number.
Ÿ converts a fraction to a decimal, or converts a
decimal to a fraction, if possible.
If a problem contains both fractions and decimals, the
results are displayed in decimal format. However, if you
press ‡ and select n/d, the results of division will be
displayed in fraction format, when possible.
Percents ª y
Press ª after a entering a value to calculate a percent.
Press y to convert a decimal or a fraction to a percent.
Roots and Powers ¨ ¬
¬ lets you obtain the square root of a number. After
entering the number, be sure to close the parentheses.
¨ raises a number to the power you specify.
Pi ©
© enters the value of p, which is stored internally to 13
digits (3.141592653590). In some cases, results display
with symbolic
p, and in other cases as a numeric value.
Memory z |
After a calculation, press z® to store the displayed
result in memory. If memory already contains a value, the
new one will replace it. When memory contains a value
other than 0, M displays on the screen.
To recall the value from memory for use in a calculation,
press | once.
To clear memory, press ||.

Summary

Calculator Overview

Basic Operations and Features

Covers power, display, clearing, basic arithmetic, fractions, memory, and modes.

Key Functions Explained

Details integer division, fraction handling, percents, roots, powers, and Pi.

Advanced Functions

Stored Operations and Rounding

Explains Op1/Op2 for repeated operations and using Fix for rounding.

Problem Solving Modes

Covers Auto/Man modes, levels, types, feedback, scoreboard, and Man mode specifics.

Place Value and Error Handling

Details Place Value features and common error conditions and their handling.

Maintenance and Support

Battery Replacement and Troubleshooting

Provides battery replacement steps, troubleshooting advice, and support contact.

Operational Examples

Function Examples

Illustrates basic arithmetic, fractions, percents, stored operations, and problem solving.

Warranty and Service

Product Service and Warranty Details

Covers product service contacts, warranty terms, performance, and software licensing.

Feature Demonstrations

Stored Operations, Memory, and Rounding

Demonstrates examples of Stored Operations, Memory usage, and Fix key rounding.

Mode-Specific Examples

Problem Solving and Place Value Examples

Shows examples for Problem Solving modes and Place Value features.

Company Information

Texas Instruments Contact

Provides the company's address in the USA and its official website for calculators.

Overview

1. Fractions
2. Percents
3. Roots and Powers
4. Pi
5. Memory
6. Stored Operations
7. Rounding
8. Problem Solving (?)
9. Place Value (house icon)
10. Error Conditions
11. Battery Replacement
12. In Case of Difficulty

The TI-15 is a calculator and arithmetic trainer designed to assist with mathematical operations and problem-solving. It features a two-line display, each capable of showing up to 11 characters. Longer entries wrap to the second line and then scroll. For fractions, the display is limited to one line and scrolls if the problem exceeds its capacity. Results exceeding the screen's capacity are shown in scientific notation, while extremely large or small numbers trigger overflow or underflow errors.

The calculator operates using both battery and solar power, functioning in well-lit areas with its solar cell and in other light settings on battery. It includes an Automatic Power Down (APD) feature that turns off the device after approximately 5 minutes of inactivity, retaining the display, pending operations, settings, and memory. To reactivate, simply press the On key.

Basic operations are straightforward: press On to turn on the calculator and Off to turn it off. The TI-15 uses the Equation Operating System (EOS™) to evaluate expressions, following a standard order of operations: parentheses, functions preceding arguments, fractions, exponentiation and roots, negation, multiplication (including implied multiplication) and division, addition and subtraction, conversions, and finally, Enter to complete all operations.

For clearing and correcting, the Clear key deletes the character to the left of the cursor, or clears from right bottom to left top in fractions. Pressing Clear alone clears the display and any error conditions, but does not clear memory. To clear memory, press MR/MC twice. To reset the calculator completely, hold down On and Clear simultaneously for a few seconds until "MEM CLEARED" appears, restoring all default settings. This can also be done via the Mode menu.

The TI-15 offers several display indicators:

• A calculator icon indicates Problem Solving mode.
• A house icon indicates Place Value mode.
• "Fix" shows that results are being rounded.
• ►M means ►M has been pressed.
• M indicates a non-zero value in memory.
• Op1, Op2 indicates an active stored operation function.
• "Auto" means automatic simplification of fractions in calculator mode, or Auto mode in Problem Solving.
• I indicates the Integer Division function is active.
• n/d shows division results in fraction format.
• → indicates a fractional result can be simplified.
• ↑↓ indicates more entry history or menus are available, or that an entry/menu extends beyond the screen capacity.

The Mode menu allows users to configure various settings:

• n/d for decimal or fraction display.
• ? to show or hide in Op.
• OP1 OP2 to clear stored operations.
• N Y to select or reject Reset.
• U n/d n/d to select fraction format (mixed or simple).
• Man Auto for simplification procedure (manual or automatic).
• 1 2 3 for difficulty level in Problem Solving.
• + - × ÷ ? for type of operation in Problem Solving.
• -1- for Place Value function.

Fractions:

The n/d key is used to designate the numerator and denominator of a fraction. Both must be integers, and if the denominator exceeds 1000, results are displayed in decimal format. The Unit key separates the whole number from the fraction in a mixed number. The Frac key accesses a menu to specify how fraction results are displayed: U n/d (default mixed numbers) or n/d (simple improper fractions). It also allows selecting simplification methods: Man (manual) or Auto (automatic reduction to lowest terms). N/D→n/d indicates that fraction results can be simplified, and Simp enables manual simplification. Fac displays the factor used in the last manual simplification step. U converts between mixed and improper fractions, and FD converts between fractions and decimals.

Percents:

The % key calculates a percent after entering a value, or converts a decimal or fraction to a percent.

Roots and Powers:

The √ key calculates the square root of a number, requiring parentheses to close the expression. The ^ key raises a number to a specified power.

Pi:

The π key enters the value of pi, stored internally to 13 digits. Results may display symbolically or numerically.

Memory:

Pressing M after a calculation stores the displayed result in memory, replacing any existing value. M displays on the screen when memory contains a non-zero value. To recall the value, press MR/MC once. To clear memory, press MR/MC twice.

Stored Operations:

Op1 and Op2 can store an operation with a constant value for repeated use. To store, press Op1 or Op2, enter the operator and number, then press Op1 or Op2 again. Initialize with a starting value. Subsequent presses apply the operation. The computation appears on the first line, and the result on the second. The computation line can be hidden via Mode Enter. A counter shows how many times Op1 or Op2 has been pressed. To clear stored operations, go to Mode, select Op1 or Op2, and press Enter.

Rounding:

The Fix key, combined with place value keys (e.g., 1000., 100., 10., 1., 0.1, 0.01, 0.001), rounds results to a specified number of places. The internally stored value is not rounded, and calculated values are padded with zeros. Fix must be pressed each time the number of places changes. Fix alone removes fixed-decimal setting.

Problem Solving (?):

This function allows practice and testing of arithmetic skills in either Auto or Man mode. In Auto mode, the TI-15 presents problems with one missing element (e.g., 5+2=?, 5+?=7, or 5?2=7). Users can select the problem type and difficulty level (1, 2, or 3) via the Mode menu. After entering an answer, "Yes" or "No" is displayed, indicating correctness and whether the correct solution is less than or greater than the entered answer. If three incorrect answers are entered, the correct answer is shown, and a new problem is presented. A scoreboard tracks performance, displaying after every fifth problem, resetting after 100. In Man mode, users compose their own problems, entering non-negative integers and indicating missing elements with ?. The TI-15 indicates the number of solutions (one, multiple, or zero). Problems with one missing element allow three tries. Problems with two missing elements (e.g., ?+?=5) have multiple solutions and remain until manually cleared. For inequalities, > or < can be used, and only one try is given. To exit Problem Solving, press ? again.

Place Value (house icon):

In Man mode, this function helps determine the place value of a digit, or how many ones, tens, hundreds, thousands, tenths, hundredths, or thousandths a number contains, or which digit is in a specified place. To determine place value: after entering a number, press house icon and then the digit to find its place value. For repeated digits, pressing the digit again shifts to the next occurrence to the left. Via the Mode menu, users can select 11- to find how many of a certain place value are in a number, or -1- to find which digit is in a specified place. The answer appears briefly, then clears. Clear is needed before analyzing a new number. To exit, press Clear again.

Error Conditions:

• Arith Error: Arithmetical error.
• Syn Error: Syntax error.
• ÷0 Error: Attempting to divide by zero.
• Mem Error: Error storing entry in memory.
• Op Error: Error following steps for Op1 or Op2.
• Overflow Error: Overflow.
• Underflow Error: Underflow. In some cases, Clear restores the last display before the error message. Errors appear in history.

Battery Replacement:

To replace the battery, place the calculator face down, remove screws from the back, and carefully separate the front from the back. Replace the old battery with a new one. Avoid contact with other components. After replacement, press On and Clear simultaneously to reset the TI-15. Dispose of old batteries properly.

In Case of Difficulty:

Review instructions, ensure calculations were performed correctly, and reset the calculator (On + Clear). Check the battery for freshness and proper installation. If the unit doesn't turn on, the screen goes blank, or unexpected results occur, change the battery. To continue using the TI-15 until the battery can be changed, expose the solar panel to brighter light and reset the calculator.

Texas Instruments TI-15 Specifications