Undoing Division
Part of the Fundamentals section of Coddy's Math journey. Lesson 9 of 64.
x/4 means "x divided by 4", written as a fraction with x on top. In x/4 = 5 the unknown has been split into 4 parts and one part is 5. Multiply both sides by 4 to put it back together:
x/4 × 4 = 5 × 4
x = 20
On the left, dividing by 4 and multiplying by 4 cancel; on the right, 5 × 4 = 20. Check: 20/4 = 5. Whenever the unknown sits over a number, multiplying both sides by that number clears the fraction in one move.
Challenge
Solve the equation x/3 = 8 for x.
Try it yourself
x/3 = 8
Solve for x
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
All lessons in Fundamentals
1What an Equation Is
The EquationFinding the UnknownThe Same to Both SidesSolved Means AloneRecap: First Equations4Two-Step Equations
Two Layers to UndoSubtract, Then DivideAdd, Then DivideA Division InsideNegatives in Two StepsRecap: Two-Step Equations2One-Step Equations
Undoing AdditionUndoing SubtractionUndoing MultiplicationUndoing DivisionInverse OperationsRecap: One-Step Equations5Tidying First
Like TermsTerms and Numbers MixedThe Distributive PropertyDistributing a SubtractionTidy, Then SolveRecap: Tidying First