Expressions

1
Expressions

• Students will be able to identify, write, and
  evaluate simple expressions.

2
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.

3
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.

4
Algebraic Expression

• An algebraic expression contains a variable.
• Here are some examples
• a 3
• 6 y
• t 32
• 5p

5
Algebraic Expressions

• There are several ways to write multiplication in
  an expression.
• 7 x a can be written as
• 7a
• 7(a)
• 7 ? a

6
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.

7
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.

8
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

9
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

10
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.