You need to know the following:
- A square root such as is a surd. (But not, eg. )
- Surds multiply and divide as normal: and
- Surds simplify by decomposing them into a product with a square number, and applying the root to that square - eg.
Test Yourself: Simplifying Surds
- You can rationalise surds of the form by multiplying by - this keeps the fraction the same value, but 'eliminates' the surd from the bottom: