Education Technology

Expressions and Equations / What is a Variable?

Activity 2 of 18
In this lesson students evaluate expressions, write expressions that correspond to given situations, and use expressions and formulas to solve problems.

Planning and Resources

Objectives
Students should understand that a variable can take on any one of a range of values.  They recognize an algebraic expression as one involving some combination of variables, numbers and mathematical operations.

Vocabulary
expression
variable
constant

Standard:

Lesson Snapshot

Understanding

Algebraic expressions specify numerical calculations using numbers and letters or symbols standing for numbers.

What to look for

Students leave behind the symbol “x” for multiplication and come to understand that the juxtaposition of a number and a variable such as 3x implies multiplication between 3 and x.

Sample Assessment

If a=115 and b=45, what would be the value of the expression b+(a - b)?

a 115  b. 185  c. 205  d. 275