Surds

Simplify, combine and multiply surds, then rationalise denominators while keeping answers exact.

Curriculum rangeYears 9–11

Square factor (a)

Remaining number (b)

$\sqrt{18}$

Split into a square factor times 2: $18 = 9 \times 2$ , and $\sqrt{9} = 3$ comes out of the root.

= $3\sqrt{2}$