11 Variables and Expressions

1
1-1 Variables and Expressions

• Identify variables, numerical expressions, and
  variable expressions
• Write variable expressions for word phrases

2
Variables and Expressions

• Thomas needs 2 to ride the bus to Videoland. How
  much can he spend on video games for each amount
  in the table?

numerical expresion
variable expresion
variable
3
Definitions

• A variable is a letter that stands for a number
• A variable expression is a mathematical phrase
  that uses variables, numerals, and operation
  symbols
• A numerical expression is a mathematical phrase
  that uses numerals and operation symbols

4
Variable or Numerical?

• 50 5
• Numerical expression (there are no letters)
• c 5
• Variable expression c is the variable

5
Your turn!

• 8 x
• variable expression x is the variable
• 100 6
• numerical expression
• d 43 9
• variable expression d is the variable

6
Writing Variable Expressions

• Bagels cost .50 each. Write a variable
  expression for the cost of b bagels.
• .5b or 1/2b
• h decreased by 7
• h 7
• the quotient of 42 and a number s
• 42 or 42 s
• s

7
Your turn!

• twice x
• 2x
• j decreased by 9
• j 9
• the product of a number d and 16
• 16d
• h divided by 7
• h 7