Overview
Cambridge 9709 mark schemes can look like a secret code, filled with cryptic abbreviations like M1, A1, and FT. These are not random; they are the examiner's precise instructions for awarding marks. Understanding this notation is the single most important skill for accurately self-assessing your work, identifying where you lost marks, and learning how to secure them next time.
The Core Trio: M, A, and B Marks
At the heart of every 9709 mark scheme are three fundamental types of marks. The M1 mark is a Method mark, awarded for attempting to use a correct mathematical process. For example, if you try to use the quotient rule to differentiate a fraction, you will likely earn an M mark even if you make a slip in the calculation. The A1 mark is an Accuracy mark, awarded for a correct answer or intermediate step. These are almost always dependent on the preceding method mark being earned; you can't get credit for a correct answer that comes from incorrect working. Finally, the B1 mark is an independent or Bonus mark, awarded for a correct statement or result that isn't dependent on a specific method, such as correctly stating a required formula or identifying a coordinate from a graph.
Dependency and Following Through: DM and FT
Many A-Level Maths problems involve multiple steps, and the marking reflects this. A DM1 mark is a Dependent Method mark. This means you can only earn this method mark if a previous M mark has already been awarded. It signals that the step is a logical continuation of a prior process. Even more important is the concept of FT (or ECF), which stands for Follow Through (or Error Carried Forward). This generous rule allows you to earn subsequent marks even if you made an earlier mistake. For instance, if you calculate a value incorrectly in part (a) but then use that incorrect value correctly in part (b), you can still earn the method marks in part (b). This system is designed to reward correct mathematical thinking, even when an initial error has occurred.
Proving and Precision: AG, cao, and art
These abbreviations deal with the nature and precision of your final answer. When you see AG (Answer Given), it means the final answer is provided in the question itself. In these cases, you earn zero marks for just writing the answer; the marks are awarded for showing the detailed, logical working that leads to that given result. cao means correct answer only. This is a strict condition indicating that no follow-through from previous errors is permitted for this specific mark; the answer must be exactly as stated and derived from fully correct working. In contrast, art stands for anything rounding to. This gives a little flexibility, allowing credit for an answer that is numerically equivalent to the one in the mark scheme, even if expressed with more or fewer decimal places, as long as it would round to the specified value (e.g., an answer of 2.45 would be accepted for 'art 2.5').
Interpreting Your Working: soi, oe, isw, and nfww
Examiners use a set of codes to guide how they interpret what you have written on the page. soi means seen or implied. You can earn the mark if the examiner sees the required step written down, or if it is clearly implied by the correct subsequent work you have done. A very common and helpful abbreviation is oe, or or equivalent. This indicates that there are other valid ways to express the answer; for example, if the mark scheme says 1/2, an answer of 0.5 or 50% would also be accepted. isw means ignore subsequent working. If you write down a correct answer and then continue with some incorrect working, the examiner will award the mark for the correct answer and simply ignore the incorrect work that followed it. The opposite of this is nfww, or not from wrong working. This is a safeguard to ensure that a correct answer that appears coincidentally from flawed logic does not receive credit.
Frequently asked questions
This section covers Frequently asked questions — ranked by what Cambridge examiners return to most often in past papers.
What's the difference between an M1 and a B1 mark?
A B1 mark is awarded for a correct piece of information or a simple calculation, often stated without extensive working, like writing down the correct derivative of e^x. An M1 mark is for demonstrating knowledge of a mathematical process or method, such as attempting integration by parts, regardless of whether the final answer is accurate.
How does 'Follow Through' (FT) actually work when I mark my paper?
When you see FT on a mark scheme, check the corresponding step in your own work. If you used a correct method but substituted an incorrect value from a previous part of the question, you can still award yourself that method mark. It's Cambridge's way of rewarding you for correct thinking.
Can I get an A1 mark if my M1 mark was wrong?
Almost never. Accuracy (A1) marks are dependent on the associated Method (M1) mark. If your method for reaching an answer was fundamentally flawed, you cannot be awarded the accuracy mark for the answer itself. This is a crucial principle in how to read a mark scheme and ensures marks are given for valid mathematical reasoning.