## Rounding to Significant Figures

To round a number to 2 significant figures (s.f.) we look at the first 3 digits. To round a number to 3 decimal places we look at the first 4 digits. Zeros at the beginning of a number are ignored (e.g. when rounding 0.0007543 to 2 significant figures the 3 digits we would examine are 754). If the final digit is 5 or more we round up. If the final digit is less than 5 we round down.