This GCSE Foundation Maths revision lesson covers: Simplifying algebraic expressions (collecting like terms) Substitution into expressions (including negatives) Forming expressions from words Finding the nth term (increasing and decreasing sequences) Designed for students currently working at Grade 3–4, aiming for a secure Grade 4/5 pass. Includes: Interactive revision lesson (HTML — open in any browser) 3 warm-up retrieval questions 12 tiered practice problems (Green / Amber / Red difficulty) Typed-answer questions — students write answers, not just click Full worked examples for every question Mistake Detective — the 5 most common errors examiners see Examiner Lens — how marks are awarded and lost Mastery checklist for self-assessment Printable worksheet (PDF — clean classroom version) Suggested classroom use: 15-minute lesson starter Homework task Cover lesson Revision for Grade 4 boundary students Independent practice Tutor sessions Estimated lesson time: 15–20 minutes. No login or account required. Works on phones, tablets and computers. Works offline after opening. This lesson is part of a structured 10-unit GCSE Foundation revision pathway. Students can complete it independently with instant feedback and progress tracking. Teachers are welcome to share the page link with students for classroom or homework use. Created by a practising GCSE Maths tutor. If you use this lesson in class, feedback is greatly appreciated.