Decimal places and significant figures - My GCSE Science Oct 31, 2018 · Zeros after non-zero digits within a number with decimals are significant. 34,000 (2 s.f.) 34.000 (5 s.f.) Rounding significant figures. If you’re asked in the exam to round a number to a specified number of significant figures, do the following: Identify the significant figures in that number using the rules above.