Texas Instruments TI15TK Teacher Guide - Page 41

What’s the Problem

Page 41 highlights

What's the Problem? Overview Students will connect number sentences to problem situations and use addition, subtraction, multiplication, and division to solve the problems. Grades 2 - 5 Math Concepts Materials • addition, subtraction • multiplication, division (Grades 3 - 5) • number sentences (equations) • inequalities (Grades 3 - 5) • TI-15 • counters • pencil • student activity (page 37) Introduction 1. On a sentence strip or on the overhead, display a number sentence such as "8 + 2 = ?" Have students brainstorm situations and related questions that this number sentence could be representing. For example, "If I bought eight postcards on my vacation and I had two postcards already at home, how many postcards do I have now?" 2. If necessary, have students act out the situation with counters and determine that the value of "?" is 10. 3. Demonstrate how to display this equation on the calculator, and how to tell the calculator what the value of ? is. 4. Now display an equation such as ? - 10 = 5. Have students brainstorm situations and related questions that this number sentence could be representing. For example, "I had some money in my pocket, and I spent 10 cents of it. I only have 5 cents left. How much money did I have in my pocket to begin with?" Have students practice the keystrokes necessary to display this equation and test the value they determine for "?". 5. Over a period of time, continue to introduce students to different types of number sentences to explore. For example, ? - 8 < 5 (which has 13 whole number solutions) and ? x ? = 24 (which has 8 solutions of whole number factor pairs) and ? x 4 = 2 (which has no whole number solution). ³ To display this equation on the calculator, put the calculator in Problem Solving mode by pressing the ‹ key. Then enter the equation 8 + 2 = ? and press ®. The calculator display (1 SOL) tells how many whole number solutions there are to the equation. To test your solution to the equation, enter the value of 10 and press ®. The calculator will display YES. ³ If an incorrect value is tested for ?, the calculator will display NO and provide a hint. For example, if a student tests 5 for the equation ? - 10= 5, the calculator displays NO, then shows 5 - 10 < 5, and then returns to the original equation. © 2000 TEXAS INSTRUMENTS INCORPORATED TI-15: A Guide for Teachers 34

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© 2000 T
EXAS
I
NSTRUMENTS
I
NCORPORATED
TI-15: A Guide for Teachers
34
What’s the Problem?
Grades 2 - 5
Overview
Students will connect number sentences to problem
situations and use addition, subtraction,
multiplication, and division to solve the problems.
Math Concepts
• addition,
subtraction
• multiplication,
division (Grades
3 - 5)
• number sentences
(equations)
• inequalities
(Grades 3 - 5)
Materials
• TI-15
• counters
• pencil
• student
activity
(page 37)
Introduction
1.
On a sentence strip or on the overhead, display a
number sentence such as “8 + 2 = ?” Have
students brainstorm situations and related
questions that this number sentence could be
representing. For example, “If I bought eight
postcards on my vacation and I had two
postcards already at home, how many postcards
do I have now?”
2.
If necessary, have students act out the situation
with counters and determine that the value of “?”
is 10.
3.
Demonstrate how to display this equation on the
calculator, and how to tell the calculator what
the value of ? is.
4.
Now display an equation such as ? - 10 = 5. Have
students brainstorm situations and related
questions that this number sentence could be
representing. For example, “I had some money in
my pocket, and I spent 10 cents of it. I only have
5 cents left. How much money did I have in my
pocket to begin with?” Have students practice
the keystrokes necessary to display this equation
and test the value they determine for “?”.
5.
Over a period of time, continue to introduce
students to different types of number sentences
to explore. For example, ? - 8 < 5 (which has 13
whole number solutions) and ? x ? = 24 (which
has 8 solutions of whole number factor pairs)
and ? x 4 = 2 (which has no whole number
solution).
³
To display this equation
on the calculator, put
the calculator in
Problem Solving mode
by pressing the
key.
Then enter the equation
8 + 2 = ?
and press
®
. The calculator
display (
1 SOL
) tells
how many whole
number solutions there
are to the equation.
To test your solution to
the equation, enter the
value of
10
and press
®
. The calculator will
display
YES
.
³
If an incorrect value is
tested for
?
, the
calculator will display
NO
and provide a hint.
For example, if a
student tests 5 for the
equation
? - 10= 5
, the
calculator displays
NO
,
then shows
5 - 10 <
5
,
and then returns to the
original equation.