Add integers
7.NS.2: Apply and extend previous understandings of multiplication and division and
of fractions to multiply and divide rational numbers.
a. Understand that multiplication is extended from fractions to rational numbers
by requiring that operations continue to satisfy the properties of operations,
particularly the distributive property, leading to products such as (–1)( –1) = 1
and the rules for multiplying signed numbers. Interpret products of rational
numbers by describing real-world contexts.

Students practice and justify their understanding of multiplication of integers by
using the Integer Game.

Students explain that multiplying by a positive integer is repeated addition and
that adding a number multiple times has the same effect as removing the
opposite value the same number of times

Students use the properties and facts of operations to extend multiplication of
whole numbers to multiplication of integers.

Students use the rules for multiplication of signed numbers and give real-world
examples.
Integer Game: (+*+) picking up sets of positive values
(+*-)  picking up sets of negative values
(-*+)  laying down sets of positive values
(-*-)  laying down sets of negative values
#8
Spiral Review #2
WKSP
Procedure
https://www.youtube.com/watch?v=2k_jS1zVLWw
Stand and Deliver
HW
Media
Student Outcomes
Standard
Pre Requisite
Multiply Integers
Multiply Integers
From the Integer Game, what would your score be if you were given the
following three cards?
5
5
5
If the cards repeat, then
TOTAL VALUE = the number of cards given times the value of each card
Positive times a Negative
From the Integer Game, what would your score be if you were given the
following three cards?
-5
-5
-5
If the cards repeat, then
TOTAL VALUE = the number of cards given times the value of each card
Exercise:
1. Generate real-world situations that can be modeled by 4 x (-7).
2.
Gary and Thomas are playing a game with number cards. At the end of the game,
Thomas still has 5 cards. If the value of each card is -50 points, how many points
does Thomas have?
a) -250
b) -10
c) 10
The first two cases are about being given cards.
What if the cards are taken?
d) 250
Multiply Integers
Negative times a Positive
From the Integer Game, what would your score be in the following three cards were
taken from you?
5
5
5
If the cards repeat, then
TOTAL VALUE = the number of cards taken times the value of each card
Negative times a Negative
From the Integer Game, what would your score be in the following three cards were
taken from you?
-5
-5
-5
If the cards repeat, then
TOTAL VALUE = the number of cards taken times the value of each card
Exercise:
1. Generate real-world situations that can be modeled by each of the following
multiplication problems.
a. -3 x 5
b. -6 x (-3)
2.
How do we determine if the product of two signed numbers will be positive or
negative?
same signs  answer is _______________
different signs  answer is ________________
Multiply Integers
Multiply Integers
Name: __________________________________
Pre-Algebra
1.
Date: ______
Exit Ticket
Natalie is playing the Integer Game and only shows you the four cards shown
below. She tells you that the rest of her cards have the same values on them and
match one of these four cards.
a. If all of the matching cards will increase her score by 18, what are the matching
cards?
b. If all of the matching cards will decrease her score by 12, what are the matching
cards?
2.
Create a real-life example that can be modeled by the expression -2 x 4 and then
state the product.
Multiply Integers
Name: _______________________________________
Pre-Algebra
Date: _____
HW #8
Lesson Summary

Multiplying integers is repeated addition and can be modeled with the Integer Game. If a 3 x a corresponds
to what happens to your score if you get three cards of value a, then (-3) x a corresponds to what happens
to your score if you lose three cards of value a.

To multiply signed numbers, multiply the absolute values to get the absolute value of the product. The sign
of the product is positive if the factors have the same sign and negative if they have opposite signs.
1. Describe sets of two or more matching integer cards that satisfy the criteria in each
part below:
a. Cards increase the score by eight points
b. Cards decrease the score by 9 points
c. Removing cards that increase the score by 10 points.
d. Removing cards that decrease the score by 18 points.
2. You have the integer cards shown below when your teacher tells you to choose a
card to multiply four times. If your goal is to get your score as close to zero as
possible, which card would you choose? Explain how your choice changes your
score.
Multiply Integers
3. Explain why (-4) x (-5) = 20. Use an example from the Integer Game to support your
reasoning.
4. Sherry is playing the Integer Game and is given a chance to discard a set of matching
cards. Sherry determined that if she discards one set of cards her score will increase
by 12. If she discards another set, then her score will decrease by eight. If her
matching cards make up all six cards in her hand, what cards are in Sherry’s hand?
Are there any other possibilities?
Review:
5. Use absolute value to express the distance between 4 and -1.
6.
3
Simplify: − 8 +
4
5
=