Topics · Edexcel GCSE Maths (1MA1)

Surds

Higher only

A surd keeps its exact value until the last step. Simplify the root before you do anything else with it.

Exam-style questionNon-calculator2 marks

Simplify $\sqrt{72} + \sqrt{50}$ .

Give your answer in the form $a\sqrt{2}$ , where $a$ is an integer.

See why

Which way of splitting 72 simplifies $\sqrt{72}$ fully?

$\sqrt{72}$

Pick a pair of factors of 72.

New contextNon-calculator2 marks

Expand and simplify $(2 + \sqrt{3})^2$ .

Give your answer in the form $a + b\sqrt{3}$ , where $a$ and $b$ are integers.

Surds, exact calculations and rationalising

Short hands-on steps, then exam questions on this topic.

Higher tier only.
When a question asks for an exact answer, a rounded decimal loses the accuracy mark.
Rationalising a denominator, such as 12/√3 = 4√3, comes up in the same questions.