Flashcards for WJEC GCSE Maths Writing an Expression, covering the key formulae, methods and definitions you need to recall for Unit 1, Unit 2 and Unit 3. 20 cards, matched to the WJEC GCSE Maths (3320QD) specification. Recall questions account for roughly 50% of marks at GCSE Maths, so these target the marks you can secure before the paper starts.