±«Óătv

Working with surdsRules of surds

Surds are square roots which can’t be reduced to rational numbers. Some can be simplified using various rules or by rationalising the denominator.

Part of MathsNumerical skills

Rules of surds

Remember that there are three simple rules of surds:

Rules of surds
1\(\sqrt a \times \sqrt a = a\)
2\(\sqrt {ab} = \sqrt a \times \sqrt b\)
3\(\sqrt {\frac{a}{b}} = \frac{{\sqrt a }}{{\sqrt b }}\)
1
Rules of surds\(\sqrt a \times \sqrt a = a\)
2
Rules of surds\(\sqrt {ab} = \sqrt a \times \sqrt b\)
3
Rules of surds\(\sqrt {\frac{a}{b}} = \frac{{\sqrt a }}{{\sqrt b }}\)
Next up
Test your understanding
Previous page
Rationalising the denominator

More guides on this topic

Related links