5 Significant Figures

Significant Figures

• Significant figures − Numbers of digits up to which one could express a quantity measured

Rules for Arithmetic Operations with Significant Figures

• Addition or subtraction − The final result should retain as many decimal places as there are in the number with the least decimal places.

Example − The sum of three numbers 1.3 m, 2.76, and 3.071 m is 7.131. It is rounded off to 7.1 m [up to smallest number (1.3 m) of decimal places (2)].

• Multiplication and division − The final result should retain as many significant figures as there are in the original number with the least significant figures.

Example − Suppose x = 2.7 and y = 0.326

Therefore, xy = 0.8802

As least number of significant figure is 2 (in x = 2.7), therefore, the final result is rounded off to xy = 0.88

For division, suppose x = 2.367 and y = 1.3, then, but the final result is rounded off to