8th Grade · Expressions & Equations
Inverse Operation
8.EE.C.7b
Definition
The operation that reverses another, such as subtraction undoing addition or division undoing multiplication. Used to isolate the variable when solving equations.
Teach it
Where it is taught, with guided notes, practice, homework, an exit ticket and an interactive Teacher Deck.
Examples
- For 2x+3 = 11: subtract 3 (inverse of +3), then divide by 2 (inverse of ×2).
- Undo operations in reverse order — addition/subtraction first, then multiplication/division.
Key rule
Apply the same inverse operation to both sides to keep the equation balanced.
Memory hook
Undo each operation with its opposite.