How to Show Working for Full Marks in IGCSE Add Math

The Cambridge 0606 syllabus says it plainly: candidates are expected to show all necessary working. What it doesn’t say, and what changes students’ grades when they finally understand it, is how the marks are constructed. Add Math is marked in three currencies, and you can only protect what you can name.

M, A and B marks

• M marks (method): awarded for a correct method attempted, quoting the quadratic formula with values substituted, writing $\frac{dy}{dx} = 0$, setting up $u$, $v$ for the product rule. M marks do not require the right answer. They are independent of arithmetic.
• A marks (accuracy): the correct result of that method. A marks are dependent, no method shown, no A mark, even with the right answer. A bare correct answer to a 4-mark question can score 1 or even 0.
• B marks (independent): correct statements or values not tied to a method, a sketch feature, stating the period of a function, the value of a constant.

The grade implication: a student who writes full method but slips arithmetic in three questions might lose 3 accuracy marks. A student who does the same maths mentally and writes only answers can lose 12. Same mathematics, one grade apart.

The six working habits that bank method marks

1. State the general form before substituting. Formula first, numbers second: "$x = \dfrac{-b \pm \sqrt{b^2 - 4ac}}{2a}$" then the substituted line. The quoted-and-substituted line is where M marks live, see it in action in the differentiation technique guide.
2. Write the defining equation of every standard procedure. $\frac{dy}{dx} = 0$ for stationary points. $b^2 - 4ac < 0$ for no real roots. $|2x - 1| = \pm(x + 3)$ for modulus equations. These single lines are frequently a mark each.
3. One step per line, vertically. Examiners award what they can find. A vertical chain of equivalent statements is auditable; a paragraph of mathematics is a search problem.
4. Keep exact values until the final line. Premature rounding poisons the accuracy marks downstream. On Paper 1 stay in surds, fractions and $\pi$; on Paper 2 carry full calculator precision and round once, at the end, to the accuracy the question demands (3 significant figures unless told otherwise).
5. Answer the command word. “Show that” with the result given means every connecting step must appear, you are being marked on the journey, since the destination is printed on the paper. Full decode in command words.
6. Conclude in words when the question asks a question. “Since $b^2 - 4ac = -8 < 0$, the line does not meet the curve.” The final B/A mark often requires the stated conclusion, not just the inequality.

What examiners keep reporting

Session after session, 0606 examiner reports list the same working failures: answers with no visible method, rounding mid-solution, both attempts left uncrossed, and “hence” instructions ignored (using a fresh method where the previous part was required). All four are habits, all four are fixable in weeks, they appear with fixes in common exam mistakes.

How to retrain your working

Take any past-paper question you can already solve. Solve it again writing working for a stranger, someone who must reconstruct your reasoning from the page alone. Then mark it against the real scheme, counting M, A and B separately (past papers guide). Most students discover they have been silently donating 10–15% of the paper.

This is the single highest-leverage fix in Add Math, and it is precisely what a specialist tutor does every week: read your working the way the examiner will, and tell you which marks you just lost. Teacher Rig has done that for 8 years. First class is a free 1-hour trial, online, booked over WhatsApp.