Its irrelevant to the topic, what the ACTUAL thing to do is, give your answer to the least amount of significant figures provided in the questions. Say the question is, a car is travelling at 8.059m/s for 4.5 seconds, what is the Distance travelled? The Speed is given to 4sf, however time is given to 2sf so the answer is to 2sf as you can not be more accurate than this. Its kinda hard to understand, let me know if and what you dont understand. And at gcse if you give it to like 4 sf i think you will always get the mark unless it tells how many to give.