A Division Inside
Part of the Fundamentals section of Coddy's Math journey. Lesson 20 of 64.
x/2 + 3 = 8: the unknown is halved, then 3 is added. Reverse order again: subtract 3 first, then undo the halving by multiplying by 2.
x/2 = 5
x = 10
Check: 10/2 + 3 = 8. True.
There is also a shortcut: multiply everything by 2 straight away, which clears the fraction in one move (x + 6 = 16), then subtract 6. Both roads have two steps and both are correct; pick the one whose arithmetic you like better. Clearing fractions early becomes the standard trick when there are several of them.
Challenge
Solve the equation x/4 + 5 = 9 for x.
Try it yourself
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