Overview
For Cambridge Cambridge past paper revision, one wrong number does not always kill the whole question — if your later method stays consistent and the scheme allows error carried forward (ECF).
What ECF means
For Cambridge Cambridge past paper revision, you make an error early (often arithmetic). Later parts use your wrong value correctly. Examiners award follow-through marks when the scheme says ecf or ft.
When ECF does NOT apply
For Cambridge Cambridge past paper revision, ---
- Wrong method (not wrong number)
- Wrong physics setup
- You restart with the correct value mid-question without showing link
- Scheme says cao (correct answer only)
How to write for ECF
For Cambridge Cambridge past paper revision, ---
- Label intermediate results clearly (r = 0.24)
- If you know step (a) is wrong, continue (b) with your r and state it
- Do not silently switch to the back-of-book answer
Self-marking ECF
For Cambridge Cambridge past paper revision, when marking, ask: *If I accept my wrong value from line 2, is line 5 logically correct?*
If yes, award the ecf marks the scheme lists.
Practice on 9709 / sciences
Pick one multi-part calculation from a recent [9709](/blog/cambridge-9709-a-level-mathematics-past-papers-guide) paper. Deliberately use a wrong (a) and practise marking (b) with ecf — builds exam-day calm.
FAQ
For Cambridge Cambridge past paper revision, no — MCQ is binary.
Does ECF apply to MCQ?
Can MarkScheme show ECF?
Feedback references scheme structure; always verify with the official PDF.