Mathematics for IGCSE & O level - Using A Calculator (Section 3 - No. 22)
When do you round your answer to significant figures?
When the answer is not clear to the calculated process.
When there is a real-life situation.
When the problem is set in a real-life output.
When the statement does not tell you the needed accuracy.
Forklaring
If the statements in the questions are not exact, you should give the answer to three significant figures.