Lesson Plan

State what it means for two expressions to be equivalent: they produce the same value for every substitution of the variable -- not just one specific value

Use substitution of at least two values to test whether two expressions might be equivalent, and recognize that a single mismatch is sufficient to prove they are not equivalent

Confirm equivalence algebraically by simplifying both expressions using properties of operations (distributive property, combining like terms) from 6.EE.A.3

6.EE.A.4

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 y + y + y and 3y are equivalent because they name the same number regardless of which number y stands for.