MS After School Intervention
Unit: Simplifying Expressions
Theme: Entertainment
Day 2 Lesson
Objective
Students will write and evaluate algebraic expressions to represent unknown quantities.
Common Core Standards:
6.NS.2 Write, read, and evaluate expressions in which letters stand for numbers.
6.NS.2a Write expressions that record operations with numbers and with letters
standing for numbers. For example, express the calculation “Subtract y from 5” as
5y
6.NS.2b Identify parts of an expression, using mathematical terms (sum, term,
product, factor, quotient, coefficient); view one or more parts of an expression
2(8  7) as a product of two factors; (8  7) as both a single entity and a sum of two
terms.
6.NS.2c Evaluate expressions at specific values of their variables. Include
expressions that arise from formulas used in real-world problems. Perform
arithmetic operations, including those involving whole-number exponents, in the
conventional order when there are no parentheses to specify a particular order
(Order of Operations). For example, use the formula V  s 3 and A  6s 2 to find the
volume and surface area of a cube with sides of length s = 1/2.
Materials
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Overhead projector or document camera
Chart paper
Tape
Number Cubes
Envelopes
Moving with Math: Algebra (MH5)
QuietShape algebra tiles
“I Want a Souvenir Cup” resource sheet
“Zookeeper for a Day Stations” resource sheets
“Zookeeper for a Day Student Answer Sheet” resource sheets (one per student)
“By the Roll of the Dice Expressions” resource sheets (cut out prior to lesson)
“Activity Solutions” resource sheet
“3 – 2 – 1 Reflection” resource sheet (one per student)
“I Want a Souvenir Cup!” (15 minutes)
Arrange students into groups of four. Read the following scenario to students: “You and
your friends are going to the Ravens game. You have offered to purchase drinks for each
of your friends. If you spend exactly $20, you receive a Ravens souvenir cup. What
combinations of drink purchases could you buy to reach exactly $20?”
Post the Beverage Menu through your document camera or overhead projector and allow
time for students to work together as a group to come up with their different
combinations. Ask students the following questions:
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How many drinks were you able to purchase?
How did you arrive at your answer?
What drink option will allow you to purchase the largest quantity with your
$20?
If you wanted to purchase n number of bottled waters, how would you write
this as an expression? What does your variable represent?
(Note: Answers will vary. A sample answers may be: 4 lemonades, 4 iced teas, and 4
sodas.)
Representing Algebraic Expressions with Algebra Tiles (20 minutes)
Complete the Introductory Activities on page 34 of Moving with Math: Algebra (MH5).
Once completed, write two additional examples on the board and have students use the
QuietShape algebra tiles to solve.
Teacher Option: Create large algebra tiles using colored paper to display on the board.
Inside-Outside Circle (15 minutes)
During this strategy, students form two different circles: half of the group stands in a
circle facing outward while the other half forms a circle around them facing inward.
Students exchange information until the teacher signals the outer circle to move in one
direction. The students now have a different partner with whom to exchange.
Inside Circle: The teacher will display 3x – 4 on the document camera using algebra
tiles. The inside circle will explain to their Outside Circle partner what expression those
tiles represent and why.
The outside circle will move in a clockwise direction one space.
Outside Circle: The teacher will write the following expression on the board: 5 + 2x.
The outside circle will explain what tiles you would use to represent this expression and
why.
“Zookeeper for a Day” (20 minutes)
Students will work with a partner during this task. Each pair will receive an envelope
with a specific zoo labeled on the outside. Inform them that their job for the day is to
feed the animals, but they must first determine either the area or perimeter of the enclosed
area. There is a consistent measurement among zoos, and the other information needed
will be in their envelope.
Give each student a “Zookeeper for a Day” Answer Sheet. Students will travel around
the room and complete two tasks at each animal station:
1. Write the expression that models the area or perimeter using the information
given from the poster.
2. Look inside your envelope to find the missing dimension and determine the area
or perimeter of the enclosed area.
Once students have completed their rotation, they will go back to their seats and answer
the follow-up question at the bottom of their Answer Sheet.
“By the Roll of the Dice” (15 minutes)
Hand out an expression to each student. Have approximately five students come up to
the front of the room with their expression. Roll a number cube. The number it lands on
will represent the value of the variable. Have students stand in line from least to greatest
after they have determined the value of their expression by substituting the value for the
variable. Have the remaining seated students determine if their expressions are in order
from least to greatest.
Repeat activity with a new group of students coming up to the front of the room and
rolling the number cube again.
Closure: “3 – 2 – 1” Reflection (5 minutes)
Students will list three things they liked about today’s lesson, two new things they
learned, and one question they might have that will be answered tomorrow.
I Want a Souvenir Cup!
Spend exactly $20 and receive a Ravens souvenir cup!
Beverages
Lemonade
Iced Tea
Soda
Bottled Water
$2.50
$1.75
$.75
$1.50
http://images.buycostumes.com/mgen/merchandiser/36644.jpg
Zookeeper for a Day Student Answer Sheet
Zoo: _______________________
Monkey Station
Giraffe Station
Area Expression:
Area Expression:
Area:
Area:
Panda Station
Zebra Station
Perimeter Expression:
Area Expression:
Perimeter:
Area:
Bird Station
Lion Station
Perimeter Expression:
Perimeter Expression:
Perimeter:
Perimeter:
Follow-Up Questions
1. Describe how you determined the area and/or perimeter for each area of the zoo.
2. How might the value of your area and perimeter compare to that of another zoo?
Monkey Station
http://www.backpocketcoo.com/blog/wp-content/uploads/funny_monkey.jpg
The monkeys are enclosed in
a fenced rectangular area that
has a length of 35 feet and a
width of w.
Giraffe Station
http://www.statue.com/images/giraffe-statue.jpg
The giraffes are in a square
shaped area with a side
length of s.
Panda Station
http://www.ibabuzz.com/politics/files/2007/12/panda02.jpg
The panda bears are enclosed
in a fenced rectangular area
that has a width of 73 feet
and a length of n.
Zebra Station
http://ed101.bu.edu/StudentDoc/current/ED101fa08/mbg/Site%20images/zebra-0003.jpg
The zebras are enclosed in
the following area below:
32 meters
x meters
Bird Station
http://media-cdn.tripadvisor.com/media/photo-s/01/22/94/92/belize-city.jpg
The tropical birds are
enclosed in a fenced square
area that has a side length
of n.
Lion Station
http://bluepyramid.org/ia/lion.jpg
The lions are enclosed in a
fenced rectangular area as
shown below:
w meters
82 meters
Salisbury Zoo
w = 60 feet
s = 32 yards
n = 90 feet
x = 28 meters
n = 25 yards
w = 50 meters
Baltimore Zoo
w = 50 feet
s = 30 yards
n = 80 feet
x = 25 meters
n = 23 yards
w = 60 meters
Virginia Zoo
w = 55 feet
s = 24 yards
n = 62 feet
x = 30 meters
n = 20 yards
w = 48 meters
Smithsonian National Zoo
w = 52 feet
s = 34 yards
n = 70 feet
x = 22 meters
n = 29 yards
w = 56 meters
Pittsburgh Zoo
w = 58 feet
s = 30 yards
n = 88 feet
x = 23 meters
n = 27 yards
w = 49 meters
Bronx Zoo
w = 70 feet
s = 42 yards
n = 100 feet
x = 35 meters
n = 29 yards
w = 75 meters
By the Roll of the Dice Expressions
14 – n
7n
n + 11
2n + 5
60
n
3n – 2
23 – n
n + 2n
20 – 3n
5n
nn
13 + n
120
n
5n – 4
60
 12
n
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Activity Solutions
Zookeeper for a Day
Monkey
A  35w
ft2
2100

1750
1925
1820
2030
2450

Salisbury
Baltimore
Virginia
National
Pittsburg
Bronx
Giraffe
A s
2
yd2

1024
900
576
1156
900
1764
2n  5
1: 7
2: 9
3: 11
4:13
5: 15
6: 17
23  n
1: 22
2: 21
3: 20
4:19
5: 18
6: 17
1:
2:
3:
4:
5:
6:
120
60
40

30
24
20
1
A  (32)( x)
2
or A  16x
A n
ft2
6570
5840

4526
5110
6424
7300
m2
448
400
480
352
368
560

625
1:
2:
3:
4:
5:
6:
60
30
20
15

12
10
529
400
841
729
841
n  11
1: 1
2: 6
3: 11
4:16
5: 21
6: 26
5n  4
3n  2
1: 1
2: 4
3: 7
4:10
5: 13
6: 16
n  2n
n n
Lion
2
yd2
1: 12
2: 13
3: 14
4:15
5: 16
6: 17
60
n
1: 1
2: 4
3: 9
4: 16

5: 25
6: 36
120
n
Bird
7
14
21
28

35
42
1: 3
2: 6
3: 9
4:12
5: 15
6: 18
5
10
15
20

25
30
Zebra
7n
1:
2:
3:
4:
5:
6:
5n
1:
2:
3:
4:
5:
6:
Panda
By the Roll of the Dice
14  n
1: 13
2: 12
3: 11
4:10
5: 9
6: 8
A  73n
20  3n
1: 17
2: 14
3: 11
4:
8
5: 5
6: 2
13  n
1: 14
2: 15
3: 16
4:17
5: 18
6: 19
60
 12
n
1: 72
2: 42
3: 32
4: 
27
5: 24
6: 22
A  82w
m2
4100
4920
3936
4592
4018
6150
3 – 2 – 1 Reflection
3 things I liked about today’s lesson:
2 new things I learned today:
1 question I still have: