Surds

A surd is a square root which cannot be reduced to a whole number. For example, the square root of 4 is not a surd, as the answer is a whole number. But the square root of 5 is not a whole number. You could use a calculator to find what the square root of 5 is, but your calculator will have to round the answer.  To be more accurate, we often leave our answers in the square root form, as a surd.

Surds aren’t scary at all!  Once you get used to them they can be fun.  You just have to learn and few simple rules and the rest is similar to algebra.

These notes summarise the rules we learnt in class.

Page 6 of this document is the ‘show that’ activity we did in class.  ‘Show that’ questions are common in GCSE exams.

Here's the homework sheet from today's lesson. Remember, we haven't covered rationalising yet so you can skip question 3b.