Name _______________________________________ Date __________________ Class __________________
At-Home Practice
CHAPTER
2
2A Understanding Variables and Expressions
Evaluate each expression to find the missing values in the
tables.
1.
a
a  12
52
64
2.
x
5x
11
55
67
12
89
13
Write an expression for each table.
3.
4.
w
r
18
12
12
6
28
22
14
7
38
32
16
8
5. Is 3x  15 an algebraic expression?
__________________________
6. Evaluate x  20 for x  7.
__________________________
7. Evaluate 12s for s  3.
__________________________
Write an algebraic expression for each situation.
8. A watch costs d dollars. How would you write the price of a radio
that costs $15 more than the watch?
________________________________________________________________________________________
9. If you divide n newspapers into 5 equal piles, how many
newspapers are in each pile?
________________________________________________________________________________________
Write each phrase as a numerical or algebraic expression.
10. 35 less than p
11. the sum of 52 and 108
_______________________________________
________________________________________
12. Write two phrases for the expression d  23.
________________________________________________________________________________________
Answers: 1. 79; 101 2. 60; 65 3. w  6 4. r  2 5. Yes 6. 27 7. 36 8. d + 15 9. n  5 10. p  35 11. 52  108
12. d plus 23; 23 more than d; 23 added to d; the sum of d and 23
Original content Copyright © by Holt McDougal. Additions and changes to the original content are the responsibility of the instructor.
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Holt McDougal Mathematics
Name _______________________________________ Date __________________ Class __________________
CHAPTER
2
Family Letter
2A Understanding Variables and Expressions
Dear Family,
Vocabulary
The student is learning how to identify and evaluate algebraic
expressions. When evaluating algebraic expressions, the
student will substitute a value for the variable and then
simplify the expression. An example of how to do this is
below.
These are the math
words we are learning:
algebraic expression
an expression that
contains one or more
variables and may
contain operation
symbols
constant a quantity
that does not change
evaluate substitute a
number for each
variable in an
expression and then
follow the order of
operations
variable a letter or
symbol that represents
a quantity that can
change
Evaluate the expression to find the missing values
in the table.
w
w • 15
10
150
Substitute the values for w in w • 15.
w  10;
10 • 15  150
12
w  12;
12 • 15  180
15
w  15;
15 • 15  225
The missing values are 180 and 225.
The student will also learn how to use a table to write an
algebraic expression.
Write an expression for the table.
What pattern do you see?
x
48
6
48  8  6
40
5
40  8  5
32
4
32  8  4
Each value for x is being divided by 8, so the expression for
this table is x  8.
An important part of solving algebraic word problems is
knowing what action or operation to perform. The table below
pairs each action to its corresponding operation.
Action
Put together
or combine
Find how
much more
or less
Put together
groups of
equal parts
Separate into
equal groups
Operation
Add
Subtract
Multiply
Divide
The student will analyze word problems and connect each
action to its operation.
Original content Copyright © by Holt McDougal. Additions and changes to the original content are the responsibility of the instructor.
1
Holt McDougal Mathematics
Name _______________________________________ Date __________________ Class __________________
CHAPTER
2
Family Letter
2A Understanding Variables and Expressions continued
There are several different ways to describe each operation.
Words
• sum
• plus
• added to
• more than
• minus
• take away
• difference of
• less than
• times
• multiplied by
• the product of
• divided by
• the quotient
of
Operation
Examples
Addition
32 plus 5  32  5
x  15  15 added to x
Subtraction
s  12  12 less than s
11  5  11 minus 5
12a  12 times a
Multiplication 3 • 6  the product of
3 and 6
125  5  the quotient of
Division
125 and 5
n  3  n divided by 3
The student is learning to translate words into math
expressions and math expressions into words.
Write each phrase as a numerical or algebraic
expression.
A. the product of 14 and x
14x
B. the difference of 127 and 115
127  115
Write two phrases for the expression 45x.
the product of 45 and x
45 times x
Reviewing these math terms with the student will help
reinforce his or her math vocabulary.
Sincerely,
Original content Copyright © by Holt McDougal. Additions and changes to the original content are the responsibility of the instructor.
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Holt McDougal Mathematics
Name _______________________________________ Date __________________ Class __________________
CHAPTER
2
Family Fun
Mind-Reading Mathematics
If you have ever wanted to impress your friends and family by being able
to read their minds, now is your chance!
Just follow these simple directions for two amazing tricks to become a
Mind-Reading Mathematician.
Game 1
Game 2
I Can Guess Your Answer
I Know What You’re Thinking
1. Think of a number.
1. Think of a number between
1 and 9.
2. Double it.
2. Multiply that number by 7.
3. Add 6.
3. Multiply that product by 3.
4. Divide it by 2.
4. Multiply that product by 11.
5. Subtract your original
5. Multiply that product by 37.
number from the quotient. 6. Multiply that product by 13.
What is your answer every
single time?
What is your answer every
single time?
_______________________________ ________________________________
Answers: Game 1: 3 Game 2: Six digit number with the same digit repeated. Sample: 111,111
Original content Copyright © by Holt McDougal. Additions and changes to the original content are the responsibility of the instructor.
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Holt McDougal Mathematics