How to Round Numbers to Three Significant Figures

To round off a number to three significant figures, we look at the digit immediately to the right of the third significant figure. If it is 5 or greater, we round up the last significant figure. If it is less than 5, we leave the last significant figure unchanged.

In the case of 1.235, the third significant figure is 5, so we round up the last significant figure:

1.235 → 1.24

Therefore, the process for rounding off a number to three significant figures involves identifying the third significant figure and making a decision based on the value of the digit immediately to its right.