Algebra · Linear equations
Chapter 1 · 5
The idea
Forming equations from problems
How to turn a worded setup into an equation: one letter for one unknown NUMBER, every other quantity built from it, and one fact that ties the expressions together — then answer the question that was asked.
A full journey — read it, play with it, work it, then earn real exam marks. Everything stays on the timeline below.
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Algebra · Linear equations
Forming equations from problems
How to turn a worded setup into an equation: one letter for one unknown NUMBER, every other quantity built from it, and one fact that ties the expressions together — then answer the question that was asked.
Why it works
Exam problems rarely say "solve this equation" — they hand you a story and expect you to build the equation. The recipe has three moves.
One letter, one unknown number
1. One letter, standing for one unknown NUMBER. "Let = Kate's age in years" — not " = Kate". The letter is a number in disguise, so it can be doubled, added, compared. Pick the quantity everything else hangs off (usually the one described last or least).Build everything else from it
2. Build every other quantity FROM that letter. "Dan is twice as old as Kate" → Dan is . "Sam is 4 years younger than Kate" → . Read relationships carefully and test with an easy number: if Kate were 10, Dan is 20 — so Dan , not . Reversing a relationship is the single most common forming error.Keep reading — free
The rest of the explanation, plus 2 worked examples you step through move by move.
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