Forming equations
Turning a worded problem into an equation by letting a letter stand for the unknown.
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Analogy
Like translating a sentence into a code you can solve.
Example
Let the number be x2x + 7 = 212x = 14x = 7
In practice
Puzzles like 'I think of a number' use this skill, and so do real bills and budgets.
Practice
Flashcards
- Turn 'double a number, add 7, get 21' into an equation.2x + 7 = 21, so x = 7.
Questions people ask
How do you start a worded algebra problem?
Choose a letter for the unknown and write down what it stands for. Then turn each phrase into maths: 'double' is 2 times, 'more than' is add, 'less than' is subtract. Build the equation, then solve it. Writing 'let x be the number of hours' makes your working clear, and examiners like seeing that step stated.
Why should you check the answer in the words?
Checking in the original wording catches mistakes in forming the equation, not just in solving it. If x = 7, double is 14, add 7 gives 21. It matches the story, so the equation was set up correctly. It also shows whether the answer makes sense in real life.