Phrases into Expressions
Part of the Fundamentals section of Coddy's Math journey. Lesson 50 of 64.
Most equations start life as a sentence. The first skill is turning a phrase into an expression: call the unknown quantity a letter, then translate the words around it.
the sum of, more than, increased by: add. the difference, less than, decreased by: subtract. twice, three times, the product of: multiply. half of, divided by, per: divide.
"5 more than twice a number": call the number n; twice it is 2n; 5 more than that is 2n + 5. "7 less than a number" is n - 7, not 7 - n: "less than" reverses the order. "Half of a number, plus 1" is n/2 + 1.
Order inside a sum does not matter: 2n + 5 and 5 + 2n are the same expression, and either is a correct translation.
Challenge
Write "3 less than four times a number n" as an expression.
Use n for the number.
Test yourselfThis lesson includes a short quiz. Start the lesson to answer it and track your progress.
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: Fractions10From Words to Equations
Phrases into ExpressionsSentences into EquationsConsecutive NumbersAge and MoneyA Perimeter ProblemRecap: Words2One-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