Surds (OCR GCSE Maths): Flashcards

An irrational number left in square root form that cannot be simplified

To keep calculations exact

$\sqrt{ab}$

$a$

Identify square factors

$5\sqrt{2}$

$3\sqrt{5}$

Only when they are the same type

Combine their coefficients

Eliminating surds from bottom of fraction

Multiply top & bottom by $\sqrt{b}$

$3 + \sqrt{2}$ (change the sign)