© 2000 T
EXAS
I
NSTRUMENTS
I
NCORPORATED
TI-15: A
Guide
for
Teachers
11
Comparing Costs
Grades 3 - 5
Overview
Students will solve a problem using division with an
integer quotient and remainder, division with the
quotient in fraction form, and division with the
quotient in decimal form and compare the results.
Math Concepts
• division
• multiplication
• fractions
• decimals
Materials
• TI-15
• pencil
• student
activity
(page 14)
Introduction
1. Introduce the following problem:
The maintenance department has determined
that it will cost $.40 per square yard to
maintain the district’s soccer field each year.
The soccer field is 80 yards wide and 110 yards
long. The six schools that play on the field have
decided to split the cost evenly. How much
should each school contribute to the soccer field
maintenance fund this year?
2. Have students use the calculator to solve this
problem in three ways:
•
Finding an integer quotient and remainder.
•
Finding the quotient in fraction form.
•
Finding the quotient in decimal form.
Collecting and Organizing Data
Students should record their procedures and results
on the Student Activity page. To help them focus on
their thinking, ask questions such as
:
•
What did you enter into the calculator to solve
the problem?
Example:
A student may have entered
80
V
110
®
to
determine the area of the soccer field, then
entered
V
0.40
®
to find the total maintenance
cost, then
W
6
®
to find the cost for each
school in fraction or decimal form.
To display an integer
quotient with a
remainder, use the
£
key.
To display a quotient in
fraction form, press
‡
"
®
to select
n/d,
then use the
W
key.
To display a quotient in
decimal form, press
‡
!
®
to select
.
,
then use the
W
key.
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