Surds

What is surds?

A surd is an irrational root that cannot be expressed exactly as a fraction — e.g. √2, √3, ∛5. GCSE Higher tier examines surd manipulation: simplifying (√50 = 5√2), rationalising the denominator (multiplying top and bottom by the conjugate), and exact-form answers in trigonometry, Pythagoras and quadratics. Decimal approximations lose marks where the question requires 'exact form'.