Identify when two expressions are equivalent (i.e., when the two expressions name the same number regardless of which value is substituted into them). For example, the expressions and are equivalent because they name the same number regardless of which number stands for.

Create equations in two or more variables to represent relationships between quantities; graph equations on coordinate axes with labels and scales.

Explain each step in solving a simple equation as following from the equality of numbers asserted at the previous step, starting from the assumption that the original equation has a solution. Construct a viable argument to justify a solution method.

Interpret expressions that represent a quantity in terms of its context.

Understand solving equations as a process of reasoning and explain the reasoning.