O/L Mathematics: The Grade 10–11 Study Guide That Targets the Marking Scheme
A complete G.C.E. O/L Mathematics guide for Sri Lankan students — the core topics, common mistakes, and how to lay out answers so you never lose method marks.
O/L Mathematics is a gateway subject — a good pass keeps your A/L stream options open. The good news: the syllabus is predictable, and most marks come from a small set of recurring topics.
The core topics to secure first
- Algebra — equations, factorisation, indices.
- Geometry — theorems, constructions, proofs.
- Trigonometry — ratios and applications.
- Mensuration — area, volume, surface area.
- Statistics & Probability.
Method marks: the habit that protects your grade
O/L Maths is marked on method, not just the final answer. Build this habit on every question:
- Write the formula you are using.
- Show the substitution of values.
- Show each working step.
- Box your final answer with units.
A correct answer with no working can score fewer marks than a wrong answer with correct method. Never skip steps to save time.
Practise in your exam medium
If you will sit the paper in Sinhala or Tamil medium, practise past papers in that medium so the terminology is second nature. Learn how to get the most from them in our past papers guide, and build your plan with the revision timetable method.
Frequently asked questions
What are the most important topics in O/L Maths?
Algebra, Geometry (including theorems and constructions), Trigonometry, Mensuration and Statistics appear in almost every paper. Master these before the lower-frequency topics.
How can I stop losing marks in O/L Maths even when my answer is correct?
Show every step. O/L Maths awards method marks, so a correct final answer with no working can still lose marks. Always write your formula, substitution and steps clearly.
Is O/L Maths available in Sinhala and Tamil medium?
Yes. The O/L Mathematics paper is offered in Sinhala, Tamil and English medium. Practise past papers in the medium you will sit the exam in.