Rationalising the Denominator Worksheet - Surds
An AQA Level 2 Further Maths (8365) worksheet on rationalising the denominator, covering single-surd and binomial (conjugate) denominators, with full worked answers.
Rationalising the denominator means rewriting a fraction so no surd is left on the bottom — a skill that comes up constantly in GCSE and A-level algebra and trigonometry. The worksheet opens with two worked examples: rationalising a single surd denominator by multiplying top and bottom by that same surd, then rationalising a binomial denominator (like 2 + √3) using its conjugate, which produces the difference of two squares and removes the surd completely.
Three differentiated tiers follow: Fluency (single surd denominators), Reasoning (binomial denominators using the conjugate method), and Problem Solving (multi-step questions combining simplifying and rationalising, plus contextualised area and geometry problems that require rationalising as an intermediate step rather than the final answer). Full worked solutions are provided on the final pages, making this suitable for independent study, homework, or self-marking
This is the second worksheet in the Surds sequence, following directly on from Surds I: Simplifying and Manipulating — students should be comfortable simplifying surds and using the difference of two squares before starting this one. Aimed at high-attaining Year 10/11 students taking the AQA Level 2 Certificate in Further Mathematics (8365) alongside GCSE, and at students bridging into A-level Maths, where rationalising denominators is assumed knowledge from the first topic on surds.\
Two PDF versions are included: a standard printable copy with name/class/date fields, and a name-free version for digital display.
Last updated: 12th July 2026.


