We strongly advise against guessing if you have the time to work out the answer. But if the invigilator says '5 minutes remaining', you need a mathematical strategy to secure every last mark on Paper 1.
1. Never Leave a Blank
Cambridge does not use negative marking. A blank answer is a guaranteed 0. A guessed answer is a 25% chance of a mark. Always fill in every bubble.
2. The 'Same Letter' Strategy
If you have 5 questions left and absolutely no clue, do not pick 'A B C D A'. Statistically, if you pick the exact same letter for all 5 questions (e.g., 'C C C C C'), you are mathematically guaranteed to get at least 1 or 2 correct, because Cambridge balances the distribution of A, B, C, and D answers across the 40 questions.
3. Look for the 'Odd One Out'
Examiners are lazy. When generating distractors for a math question, if the correct answer is 4.5, they might include 45, 0.45, and 9.0. If one answer is completely unrelated in magnitude or format to the others, it is usually a distractor, not the correct answer.
4. True/False Elimination
If an option uses absolute words like 'always', 'never', or 'must', it is usually false. In science and economics, there are always exceptions.