wunder beta🧮 Rearranging Formulas
Make any variable the subject. Use inverse operations to rearrange formulas until the letter you actually want stands alone.
3
lessons
~15 min
to learn
🔢 Math
subject
Teens
level
What you’ll learn
- The Subject of a FormulaIdentify the subject of a formula and recall the balance rule.The subject of a formula is the lone letter on one side of the equals sign, the quantity the formula returns directly. Rearranging to change the subject uses the same balance rule as solving equations: do the same thing to both sides.
- Inverse OperationsUse inverse operations to isolate a chosen variable.Addition and subtraction undo each other, as do multiplication and division, and squaring and square-rooting. To isolate a variable, peel these operations off in the reverse order they were applied, keeping the equation balanced.
- Change the SubjectRearrange multi-step formulas to make a different variable the subject.For formulas like C = 2πr or v = u + at, isolate the target letter by undoing each operation in reverse. Divide C by 2π to get r = C/(2π); subtract u then divide by t to get a = (v − u)/t.
Questions this course answers
In A = l × w, which letter is the subject?
A sits alone on one side, so it is the subject.
When you rearrange a formula, the golden rule is to:
Balance means doing the same operation to both sides.
What is the inverse of multiplying by 3?
Division by 3 undoes multiplication by 3.
Make x the subject of y = x + 7.
Subtract 7 from both sides to get x = y − 7.
Grounded in trusted sources
- Khan Academy — Algebra
- OpenStax — Elementary Algebra 2e
- BBC Bitesize — Maths
- Cuemath — Algebra
Every Wunder lesson is built from real, reputable sources — never invented.
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