A surd is a square root which cannot be reduced to a whole number. For example,√4 = 2 is not a surd. But √5 is not a whole number. You could use a calculator to find that but, instead of this, we often leave our answers in the square root form, as a surd. You need to be able to simplify expressions involving surds.

Two surds are equivalent if they express the same number:

You can simplify surds in this way:
Or you can use fraction indices:
Exercise: simplify:
solutions: a) 300√2; b) (2/3)5√2; c) a2b3c7·3√ac

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