Age and Money
Part of the Fundamentals section of Coddy's Math journey. Lesson 53 of 64.
"Three times Ana's age, plus 2, is 20. How old is Ana?" Name the unknown, a for her age, and translate: three times it is 3a, plus 2 is 3a + 2, and that equals 20.
3a + 2 = 20
Subtract 2, divide by 3: a = 6. Read it back: three times 6 is 18, plus 2 is 20. Ana is 6.
Money problems translate the same way. "You have 3 identical coins and 2 dollars, worth 20 dollars in all": the coin is c, and 3c + 2 = 20 again. Different story, same equation. The letter you choose does not matter; the translation does. Always finish by putting the number back into the sentence.
Challenge
Twice Ben's age, plus 7, is 31: 2a + 7 = 31. Solve for a.
Try it yourself
Solve for a
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