Transcript Pre-Algebra

Pre-Algebra
Chapter 1-1
Expressions and
Variables
Group Work


Review Vocabulary: Sum, Difference,
Product, Quotient, Factor
Use the review vocabulary to complete the
statement.
–
–
In the multiplication equation 12 • 5 = 60, 12 and 5
are called _________ and 60 is called the ______.
When you divide one number by another, the result
is called the ____________.
Vocabulary




Numerical Expression – consists of numbers and
operations. (4 • 5)
Variable – a letter used to represent one or more
numbers.
Variable Expression – consists of numbers, variables
and operations.
Evaluate – to evaluate or solve a variable expression,
substitute a number for each variable and evaluate the
resulting numerical expression.
Examples…

During its summer
feeding season, a blue
whale eats about 4 tons
of food every day. To
find about how many
tons of food a blue whale
eats in a given number
of days, you can multiply
the number of days by 4.

Evaluate the expression
4 • d when d = 120 to
find about how many
tons of food a blue whale
eats in a feeding season
of 120 days.
Examples…

Evaluate the expression 3 • s when s = 60 to
find how many miles Doug drives in 3 hours at
a speed of 60 miles per hour.
TWO VARIABLES>>>

Evaluate the expression when x = 10 and y =
4
–
x+y
–
xy
Checkpoint
1.
2.
3.

1.
y+8
9–x
y–x
Evaluate the expression when x = 6 and
y = 12
xy
Vocabulary

Verbal model – describes a problem using
words as labels and using math symbols to
relate the words.
Common Words and Phrases that
Indicate Operations
Addition
Subtraction
Plus
The sum of
Increased by
Total
More than
Added to
Minus
The difference of
Decreased by
Fewer than
Less than
Subtracted from
Multiplication
Times
The product of
Multiplied by
Of
Division
Divided by
Divided into
The quotient
of
Writing a variable expression

You plan to divide the 120 players in a baseball
league into teams with the same number of
players. Use a verbal model to write a variable
expression for the number of teams if you
know the number of players on each of them.