Understanding Integers ~ Lesson 6
Adding and Subtracting Integers
Using Chips
Students will understand how to use chips to add and
subtract integers.
Materials
Student Whiteboards
Smartboard or
chalkboard
Chips
Practice
problems/worksheets
Teaching Actions:
1. Addition of Integers. Explain that yellow chips
As students work with
represent the positive integers and red chips
chips, have students
represent the negative integers. A red chip cancels out articulate their process
a yellow chip to equal zero (this is called a zero pair).
and make the connection
between the chips and the
actions they took with the
integer strips.
Problem Type: Positive + Positive
3+4
SAY and Model:
Begin with 3 yellow chips
Throughout the lesson,
have students go back
and forth between models,
pictures, and words.
.
Put down 4 more
What is the answer? How do you know
Provide several examples for students to model.
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Lesson 5
p. 1
Understanding Integers ~ Lesson 6
Problem Type: Negative + Negative
(-3) + (-4)
SAY and Model:
Begin with 3 red chips
Put down 4 more red chips
What is the answer? How do you know?
Provide several examples for students to model.
Problem Type: Positive + Negative
3 + (-4)
SAY and Model:
Begin with 3 yellow chips
Put down 4 red chips
Can we put them together? What did we do with the integer
strips (cancelled out zero pairs).
Match up and remove the zero pairs.
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Lesson 5
p. 2
Understanding Integers ~ Lesson 6
What is the answer? How do you know?
Provide several examples for students to model switching
back and forth between which term is positive and which
term is negative.
2. Subtraction of Integers.
Ask students what they learned in Lesson 5 when
subtracting integers. (They learned that the operation of
subtraction changes the direction/area which means
they need to “flip” the 2nd term). Tell them they will
subtract with chips in the same way.
Problem Type: Positive - Positive
3-4
SAY and Model:
Begin with 3 yellow chips
Put down 4 more yellow chips
As students learned in
Lesson 5, subtraction is
the same as “adding the
opposite”. Through the
guided instruction and
practice, students will
further be exposed to the
connection between
addition and subtraction.
What does subtraction tell us to do? (Flip the 2nd term).
What addition problem does this model show?
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Lesson 5
p. 3
Understanding Integers ~ Lesson 6
Match up and remove the zero pairs.
What is the answer? How do you know?
Provide several examples for students to model.
Problem Type: Negative - Positive
Explicitly connect the
flipping of the chips to the
subtraction operation. If
students relate the action
of flipping to the
subtraction operation,
they will be much more
likely to differentiate
between the minus sign
as an indicator of
direction and as an
operation. This will be
important when students
work with fractions,
simplifying expressions
and polynomial.
(-3) - 4
SAY and Model:
Begin with 3 red chips
Put down 4 yellow chips
What does subtraction tell us to do? (Flip the 2nd term).
What addition problem does this model show?
What is the answer? How do you know?
Provide several examples for students to model.
07-16-11
Lesson 5
p. 4
Understanding Integers ~ Lesson 6
Problem Type: Positive - Negative
3 – (-4)
SAY and Model:
Begin with 3 yellow chips
Put down 4 red chips
What does subtraction tell us to do? (Flip the 2nd term).
What addition problem does this model show?
What is the answer? How do you know?
Provide several examples for students to model.
Provide additional practice with a combination of problem
types.
07-16-11
Lesson 5
p. 5
Understanding Integers ~ Lesson 6
Problem Type: Negative - Negative
(-3) – (-4)
SAY and Model:
Begin with 3 red chips
Put down 4 more red chips
What does subtraction tell us to do? (Flip the 2nd term).
What addition problem does this model show?
Match up and remove the zero pairs.
What is the answer? How do you know?
Provide several examples for students to model.
07-16-11
Lesson 5
p. 6
Understanding Integers ~ Lesson 6
07-16-11
Lesson 5
p. 7