Download Multiplying Integers

Basic Math
Video: 12 minutes
Multiplying
Integers
Lesson Plan
Lesson: 38 minutes
Pre-viewing
• :00 Warm up: Write “5 + 5 + 5 + 5 =” on the board. Ask students for the answer. Then write “5 x 4 =” on the board. Ask
the students for the answer. Explain to students that multiplication can be thought of as repeated addition.
2 minutes
• :02 Pre-test: Ask the students a multiplication word problem, such as: Lucy Slowe works part-time at the mall. She
makes $8 per hour. She works 10 hours a week. How much money has Lucy earned in 5 weeks? Give students time to
solve the problem. Do not tell them the correct answer until after the video. Go over the learning objectives.
4 minutes
Viewing
• :06 Playing Video: Hand out the Viewing Guide and instruct the students to follow the program, using their Viewing
Guides. Don’t hesitate to stop the program and review if the students seem confused.
12 minutes
Post-viewing
• :18 Question & Answer Session: Give the class the answer to the pre-test question: – 20. See if any parts of the program
were difficult or confusing for the students. As a class, do the first problem from each section of the Worksheet and go
over the arithmetic steps involved and the correct answer.
4 minutes
Handouts
• :22 Practicing Material: Hand out the Worksheet and give the class 6-8 minutes to complete it. Students are allowed to
use their Viewing Guides. Monitor the students’ progress, helping where needed. Go over the Worksheet as a class.
10 minutes
• :32 Applying Material: Go over the instructions for “Who’s Got It.” Tell the students that the Activity is designed to
emphasize the rules of multiplying integers. Give them 10-12 minutes to complete the Activity.
14 minutes
• :46 Wrap-up: Briefly sum up what has been covered in class and assign any homework.
4 minutes
Teacher’s Notes
Basic Math
Video: 12 minutes
Multiplying
Integers
Teacher’s Reference Guide
Lesson: 38 minutes
Learning Objectives
At the end of the module, students will be able to:
• apply rules for multiplying integers
• develop accuracy in multiplying integers
• solve word problems by multiplying integers
Materials
• Video: integers, multiplication basics, multiplying positive and negative numbers, multiplying large numbers;
12 minutes
• Viewing Guide: multiplication basics, rules for multiplying integers, multiplying large numbers
• Worksheet: fill-in-the-chart, word problems, multiplying integers
• Activity: Who’s Got It?
• Check Your Knowledge: multiple choice, word problems, multiplying integers; 50 points
Background
Students should be familiar with multiplication tables.
Preparation
Copy and cut out the Activity Cards.
Multiplying
Integers
Viewing Guide
Basic Math
Rules for Multiplying Positive and Negative Integers
If both numbers are positive, then your product is positive.
(+4) x (+6)
= +24
Anytime you multiply a negative and a positive number,
you will have a negative product.
(+4) x (-6)
= -24
If both of the numbers are negative, then your product is
positive.
(-4) x (-6)
= +24
Multiplying Basics
• multiplication is simply an extension of addition
5 + 5 + 5 = 15
5 x 3 = 15
5 x 3 = 15
3
6
9
12
15
18
21
24
27
30
4
8
12
16
20
24
28
32
36
40
3. Insert zeroes for each result where
appropriate.
4. Remember to keep the digit places lined
up.
example: 186
x 23
multiplication table: the product of multiplying
small integers
2
4
6
8
10
12
14
16
18
20
1. Multiply the digit at the far right of the
bottom number by every digit of the top
number.
2. Carry over if necessary.
product: the answer to any multiplication problem
1
2
3
4
5
6
7
8
9
10
Multiplying Large Numbers
5
10
15
20
25
30
35
40
45
50
6
12
18
24
30
36
42
48
54
60
7
8
9 10
14 16 18 20
21 24 27 30
28 32 36 40
35 40 45 50
42 48 54 60
49 56 63 70
56 64 72 80
63 72 81 90
70 80 90 100
a. 186
x 23
8
b. 186
x 23
58
c. 186
x 23
558
d. 186
x 23
558
0
e. 186
x 23
558
20
f. 186
x 23
558
3720
g. 186
x 23
558
3720
4278
FINAL ANSWER
Multiplying
Integers
Worksheet
Basic Math
A. Rules, Rules, Rules!
Fill in the chart.
Type of Integer
Multiplied By
Type of Integer
Is Equal To
negative
x
negative
=
positive
x
positive
=
negative
x
positive
=
positive
x
negative
=
Sign of the Answer
B. Word Problems
Solve the problems.
1. Julius earns $10 per hour at his job. He works 40 hours per week. How much does Julius earn in 4 weeks?
2. Tracey decides to give $1 to 5 of her close friends each day she is late for Algebra class. Algebra class meets 3 days a
week. Tracey has been late to class every day for 4 weeks. How much money has she lost?
3. In a class of 30, five students have a car. If each of the five students drives a car that can seat 4 people, how many
students can go to the basketball game after school?
C. Multiplication Rocks!
Multiply.
1. 3 x 5 =
10. (-1) x (-1) =
2. 6 x 8 =
11. 4 x 8 x -2 =
3. (-3) x (-4) =
12. 2 x (-16) =
4. (-8) x 9 =
13. 123 x (-23) =
Multiplying
Integers
Worksheet
Answer Key
Basic Math
A. Rules, Rules, Rules!
Fill in the chart.
Type of Integer
Multiplied By
Type of Integer
Is Equal To
Sign of the Answer
negative
x
negative
=
positive
positive
x
positive
=
positive
negative
x
positive
=
negative
positive
x
negative
=
negative
B. Word Problems
Solve the problems.
1. Julius earns $10 per hour at his job. He works 40 hours per week. How much does Julius earn in 4 weeks?
$10 x 40 (hours) = $400
$400 x 4 (weeks) = $1600
2. Tracey decides to give $1 to 5 of her close friends each day she is late for Algebra class. Algebra class meets 3 days a
week. Tracey has been late to class every day for 4 weeks. How much money has she lost?
$1 x 5 ( close friends) = $5
$5 (per late class) x 3 (class meeting days) = $15 per week
$15 (per week) x 4 (weeks) = $60
3. In a class of 30, five students have a car. If each of the five students drives a car that can seat 4 people, how many
students can go to the basketball game after school?
5 (students with cars) x 4 (people per car) = 20
C. Multiplication Rocks!
Multiply.
1. 3 x 5 =
15
10. (-1) x (-1) =
1
2. 6 x 8 =
48
11. 4 x 8 x -2 =
-64
3. (-3) x (-4) =
12
12. 2 x (-16) =
-32
4. (-8) x 9 =
-72
13. 123 x (-23) =
-2829
Basic Math
Multiplying
Integers
Activity
Who’s Got It?
Instructions:
1. Copy and cut out Activity Cards.
2. Shuffle the cards and hand each student a card.
3. Choose one student to start the Activity and have the student read the problem at the bottom of
the card to the class.
4. All the other students listen carefully to see if their cards contain the answer.
5. The student with the answer reads the answer aloud and then reads the question on his or her
card to the class.
6. Again, all students listen carefully to see if their cards contain the answer.
7. Play continues until all cards have been answered and the student who started the review reads
the answer to the last problem.
Basic Math
Multiplying
Integers
Activity Cards
1
2
I have 1. Who has 2 times
that number?
I have 2. Multiply -2 by this
number. What is the answer?
-12
-4
I have -4. Who has 3 times
that number?
I have -12. Subtract 2. Multiply
by -1. What is the answer?
-60
14
I have 14. Subtract 2.
Then multiply by -5. Who
has that answer?
I have -60. Multiply -1
times that number.
-30
60
I have 60. Subtract 50.
Then multiply by -3. What
is the answer?
I have -30. Multiply -5
times that number.
Basic Math
Multiplying
Integers
Activity Cards
150
-150
I have 150. Subtract 75. Then
multiply that number by -2.
1500
I have 1500. Subtract 1400.
Who has that number?
I have -150. Multiply -10 times
that number.
100
I have 100. Subtract 50.
Then multiply by -1. Who
has that answer?
400
-50
I have 400. Subtract 390.
Who has that answer?
I have -50. Multiply -8
by this number.
-20
10
I have 10. Multiply -2
by this number.
I have -20. Multiply -4
by this number.
Basic Math
Multiplying
Integers
Activity Cards
80
83
I have 80. Add 3. Who
has that answer?
I have 83. Subtract 80. Who
has that answer?
-9
3
I have -9. Multiply -3 by
this number.
I have 3. Multiply -3 by
this number.
54
27
I have 54. Multiply -2
times that number.
I have 27. Multiply 2
by this number.
-108
I have -108. Multiply -4 by
this number.
432
I have 432. Subtract 431. Who
has that answer?
Basic Math
Multiplying
Integers
Check Your Knowledge
Total Score
/ 50
A. Are You Positive?
Circle the correct answer for each of the following statements. (1 point each)
1. The answer to a multiplication problem is called the...
a) sum
b) dividend
c) product
d) multiplication tables
c) both a and b
d) none of the above
2. Multiplication is simply an extension of...
a) subtraction
b) addition
3. If you multiply a negative number by a positive number you get a...
a) negative number
b) positive number
c) dividend
d) sum
c) sum
d) none of the above
4. If you multiply two negative numbers you get a...
a) negative number
b) positive number
B. Word Problems
Solve the word problems. (5 points each)
1. The Standard Deviants’ amateur golf team has 5 golfers that are each -6 on their rounds for the day. What is the team
score?
2. Trey loses his allowance each week that he doesn’t take out the trash. Trey’s allowance is $20 a week. If Trey hasn’t
done his chores in 8 weeks, how much money has he lost?
C. M is for Multiplication!
Solve the following problems. (2 points each)
1. (-6) x (-2) =
10. 3 x 2 =
2. (-3) x 5 =
11. (-12) x (-3) =
3. 3 x (-4) =
12. 6 x (-10) =
4. 1 x (-4) =
13. (-24) x 11 =
5. (-8) x (-4) =
14. (-6) x (-6) x (-6) =
6. (-2) x 3 x (-4) =
15. (-2) x 0 =
7. (-1) x (-1) =
16. (-7) x 5 =
8. (-3) x (-3) x (-7) =
17. 8 x 5 =
9. 5 x (-6) =
18. 12 x 0 =
Basic Math
Multiplying
Integers
Check Your Knowledge
Answer Key
A. Are You Positive?
Total Score
/ 50
Circle the correct answer for each of the following statements. (1 point each)
1. The answer to a multiplication problem is called the...
a) sum
b) dividend
c) product
d) multiplication tables
c) both a and b
d) none of the above
2. Multiplication is simply an extension of...
a) subtraction
b) addition
3. If you multiply a negative number by a positive number you get a...
a) negative number
b) positive number
c) dividend
d) sum
c) sum
d) none of the above
4. If you multiply two negative numbers you get a...
a) negative number
b) positive number
B. Word Problems
Solve the word problems. (5 points each)
1. The Standard Deviants’ amateur golf team has 5 golfers that are each -6 on their rounds for the day. What is the team
score?
5 x (-6) = -30
2. Trey loses his allowance each week that he doesn’t take out the trash. Trey’s allowance is $20 a week. If Trey hasn’t
done his chores in 8 weeks, how much money has he lost?
20 x 8 = $160
C. M is for Multiplication!
Solve the following problems. (2 points each)
1. (-6) x (-2) =
12
10. 3 x 2 =
6
2. (-3) x 5 =
-15
11. (-12) x (-3) =
36
3. 3 x (-4) =
-12
12. 6 x (-10) =
-60
4. 1 x (-4) =
-4
13. (-24) x 11 =
-264
5. (-8) x (-4) =
32
14. (-6) x (-6) x (-6) =
-216
6. (-2) x 3 x (-4) =
24
15. (-2) x 0 =
0
7. (-1) x (-1) =
1
16. (-7) x 5 =
-35
8. (-3) x (-3) x (-7) =
-63
17. 8 x 5 =
40
9. 5 x (-6) =
-30
18. 12 x 0 =
0