Key Concepts in Surds
- Simplifying surds
- Adding and subtracting surds
- Multiplying and dividing surds
- Rationalising the denominator
- Expanding brackets with surds
Exam Tips for Surds
- 💡√a × √b = √(ab)
- 💡Always simplify surds by finding perfect square factors
- 💡To rationalise 1/√n, multiply top and bottom by √n
Exam Board Coverage
Surds appears on all major GCSE Maths exam boards at Higher tier.
AQA
Edexcel
OCR
Frequently Asked Questions
How do I simplify a surd?
Find the largest perfect square that is a factor of the number under the root. E.g. √48 = √(16×3) = 4√3.
What does rationalising the denominator mean?
It means eliminating surds from the denominator of a fraction. Multiply numerator and denominator by the surd (or conjugate for expressions like a + √b).