Change the value of x on a number line and see the effect on an algebraic expression.

• Students will evaluate an expression.
• Students will recognize the effect of changing a variable on the value of an expression.
• Students will relate the change in the value of an expression to the symbolic representation.

• Expression
• Variable
• Coefficient

• This lesson introduces the concept of variable and the role of variables in simple mathematical expressions.
• Students move a point along a number line and observe changes in the values of an expression. They are asked to connect the changes in the values to the coefficient of the variable term in the expression.