# Surds

### What is a Surd?

### Video

This video from *Maynooth University* gives the definition of a surd, then explains how to identify what is and isnâ€™t a surd. It also gives some helpful advice on how to recognise if a term involving a root can be simplified.

Note: All *Maynooth University* content is available for free at msc.maths.nuim.ie.

### Notes

These notes from MathCentre introduce surds, their equivalent forms and the context in which they arise. There are exercises with answers included for you to practise with.

A pdf of this document can be downloaded here.

### Interactive Exercises

This NUMBAS exercise will help you get familiar with simplifying terms involving surds.

Please click here to view this NUMBAS question in another window.

### Rationalising the Denominator

### Video

This video from *Khan Academy* gives a nice overview of the different types of fractions whose denominator you may need to rationalise. It also includes an example of how to do this for an algebraic fraction.

Note: All *Khan Academy* content is available for free at www.khanacademy.org.

### Notes

Page 7 onwards of these notes from MathCentre deal with how to rationalise fractions containing surd terms. There are exercises with answers included for you to practise with.

A pdf of this document can be downloaded here.

### Interactive Exercises

This NUMBAS exercise will let you practise rationalising the denominator in fractions involving surd terms.

Please click here to view this NUMBAS question in another window.