Identities
Class 9 · Mathematics
3 ideas in Class 9 Mathematics, explained in plain words, with games and quizzes to practise.
Algebraic Identities
Part of: Algebraic Identities
Identities are equalities that hold for every permitted variable value. They provide shortcuts for expanding expressions.
Why it matters. Recognising a structure can make a long expansion quicker.
Try it in two minutes
- Identify the expression pattern.
- Choose the matching identity.
- Substitute values carefully.
Try at home. Check an identity with a few simple values.
Factorisation
Part of: Factorisation
Factorisation reverses expansion. A common factor can be taken out, or a quadratic pattern can be recognised.
Why it matters. Factoring can reveal values that make an expression zero.
Try it in two minutes
- Find a shared factor first.
- Check for a square or difference-of-squares pattern.
- Multiply back to verify.
Try at home. Factor a few expressions and expand them to check.
Rational Expressions and New Identities
Part of: Rational Expressions and New Identities
A rational expression is a quotient of polynomials. Factoring can reveal common factors, but a denominator cannot equal zero.
Why it matters. These checks prevent invalid simplifications.
Try it in two minutes
- Factor numerator and denominator.
- Cancel only common factors.
- Keep values that make the original denominator zero excluded.
Try at home. Use a variable fraction and test which input makes its denominator zero.
What your child will practise
- Algebraic Identities: Candy Puzzle (Clue Puzzle)
- Algebraic Identities: Number Quest (Match It Up)
- Algebraic Identities: Space Quest (Flip and Match)
- Factorisation: Mission Control Quest (Collect the Answer)
- Rational Expressions and New Identities: Jungle Quick Fire (Quick Fire)
- Quiz: Algebraic Identities (8 questions)
- Quiz: Factorisation (8 questions)
- Quiz: Rational Expressions and New Identities (8 questions)