Related Procedures; Constant Operations - Texas Instruments TI-15 Teachers Manual

Related Procedures

Overview
Students will use the two constant operations (›
and œ) to compare the results of different
mathematical procedures and determine how they
are related.
Introduction
1. Have students program › with +2 and œ
with -2.
2. Have students enter
›, and read the output (
adding 2 once to 8 gives 10).
3. Have students press œ to apply the second
constant operation to the output of the first
constant operation, and then read the output
( 1 8 , which means subtracting 2 once from 10
gives 8).
4. Have students continue this process with various
numbers as their first input. Discuss their results.
(Pressing › and then œ always gets you back
to the first input number, which means › and
œ are inverse procedures.)
5. Challenge students to find more pairs of
procedures for › and œ that will follow the
same pattern and record their investigations
using the Related Procedures student activity
page.
© 2000 T I
EXAS NSTRUMENTS
8 on their calculators, press
, which means
1 10
I
NCORPORATED
Grades 2 - 6
Math Concepts
• whole numbers
• addition,
subtraction,
multiplication,
division
• fractions
(Grades 5-6)
• decimals
(Grades 5-6)
To use › and œ:
³
1. Press › (or œ).
2. Enter the operation
3. Press › (or œ).
4. Enter the number to
5. Press › (or œ).
TI-15: A Guide for Teachers
Materials
• TI-15
• pencil
• student
activity
(page 23)
and the number (for
example, T 2).
which you want to
apply the constant
operation.
The display will have
a on the left and the
1
result on the right. If
you press › (or œ)
again, the calculator
will apply the constant
operation to the
previous output and
display a at the left,
2
indicating the
constant operation
has been applied
twice to the original
input.
20