Download Expressions

Expressions
Students will be able to identify,
write, and evaluate simple
expressions.
Numerical Expression
A numerical expression is a mathematical
phrase that includes only numbers and
operation symbols.
 Numerical expressions are what you have
been working with.
 Set up a numerical expression for:

– A running back gained 42 yards in the first
half and 56 yards in the second half.
Variable
A variable is a letter or symbol that can
stand for one or more numbers.
 Numerical expressions do not contain
variables.
 Expressions that contain variables are
called algebraic expressions.
 The branch of math that involves variables
is called algebra.

Algebraic Expression
An algebraic expression contains a
variable.
 Here are some examples:

–
–
–
–
a+3
6–y
t + 32
5p
Algebraic Expressions

There are several ways to write
multiplication in an expression.
–7 x a can be written as:
–7a
–7(a)
–7 ● a
Algebraic Expressions
When a plus or minus sign separates the
expression into parts, each part is called a
term. In the expression v + 3, v is a term
and 3 is a term.
 If the term does not contain a variable it is
a constant. 3 would be a constant in the
previous example.

Algebraic Expression
A coefficient is a numerical term that
contains a variable and a number.
 In 7c + 8, 7c is a term and 8 is a term. 8
would be a constant, c is the variable, and
7 is a coefficient.

Word Expressions
Word expressions are expressions that use
words. A word expression can be
changed into a numerical or algebraic
expression.
 Three dollars less than five dollars can be
changed to 5-3.
 Two times a distance, d can be 2d

Evaluate
To evaluate a numerical expression you
find its value. If you evaluate 42 + 56,
you get a sum of 98.
 To evaluate an algebraic expression you
replace the variable with a number and
then find the value.

– a + 150, for a = 18
– 18 + 150 = 168
Evaluate

Sometimes you will need to predict and
test to solve algebraic expressions,
because you will not be given the value of
the variable every time.