A Fraction Around a Sum
Part of the Fundamentals section of Coddy's Math journey. Lesson 38 of 64.
(x + 1)/2 = 5: here the whole sum x + 1 is divided by 2. The bar of a fraction works like a bracket, so the outer layer is "divide by 2", and it is undone first: multiply both sides by 2.
x + 1 = 10
x = 9
Check: (9 + 1)/2 = 5.
Compare it with x/2 + 1 = 5, where only the x is halved and the answer is 8. The fraction bar tells you what is being divided; read it before you move.
Challenge
Solve the equation (x - 3)/4 = 2 for x.
Try it yourself
(x - 3)/4 = 2
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 Equations7Fractions in Equations
A Fraction CoefficientClearing One DenominatorTwo DenominatorsA Fraction Around a SumCross-MultiplyingRecap: Fractions2One-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