Khan Academy Static

Reasoning_about_expressions_with_unknown_variables

Learn how to study algebraic expressions containing variables whose values are unknown, and how to derive new facts about those expression by using other information. For example, given two positive integers b and c where b>c, determine which expression is greater: b/(b+c) or 0.5.

Manipulating_expressions_with_unknown_variables

Learn how to rewrite expressions with variables whose values are unknown, by using another information about those variables. For example, given that a+b=0, express a*b in terms of b alone.

Evaluating_expressions_with_unknown_variables

Learn how to evaluate expressions with variables whose values are unknown, by using another information about those variables. For example, given that a+b=3, evaluate 4a+4b.