Statistics and Significant Figures

3. Rounding
There are many conventions in rounding and here is one that many people find useful. When rounding a given number, round up if the first insignificant digit is greater than five and down if less than five. For example:
23.3 + 9.5643 = 32.8643 = 32.9
2.56 x 3.012 = 7.71072 = 7.71
Furthermore, if the first insignificant digit is exactly five, round down and round up if there are any more insignificant digits. For example:
2.75 x 1.50 = 4.125 = 4.12
36.8 / 4.571 = 7.745738 = 7.75