Significant Figure

DEFINITION

significant figure is the number obtained through measurement consisting of the numbers given (read on the measuring instrument) and the last number are estimated.

 

RULES 

1.   All the digits (1, 2, 3, 4, 5, 6, 7, 8, & 9) other than 0 (zero) certainly significant figure

2. 0 (zero) amid a number that is not zero, is certainly significant figure
        Example: 203 (3 significant figures) 

3.  0 (zero) which lies behind, the figure is not significant
        Example: 200 (one significant figure)

4.  0 (zero) which is located behind the dot, is a significant figure
        example: 2.00 (3 significant figures) 

5.  0 (zero), which is in the front, is not a significant figure
        Example: 0.2 (one significant figure) 

   CALCULATION OF SIGNIFICANT FIGURES

   Rules of multiplication and division of significant figures

   "The results of multiplication or division should have numbers as numbers by the number of significant figures the least used in multiplication or division."

   Multiplication examples of significant figures:

   Example 1: 3.4 x 6.7 = ...?The number of significant figures is at least two (3.4 and 6.7 has two significant figures). Results multiplicative is 22.78. This result must be rounded to 23 (two significant figures). 3.4 x 6.7 = 23

   Example 2: 2.5 x 3.2 = ...?The number of significant figures is at least two (2.5 and 3.2 has two significant figures). If we calculate using the calculator, the result is 8. It must be added a zero. 2.5 x 3.2 = 8.0 (two significant figures) Example 3: 1.0 x 2.0 = 2.0 (two significant figures) and not 2

   Examples division of significant figures:

   Example 1: 2.0: 3.0 = .... ?

   significant figure is at least two. If you use the calculator result is 0.666666 ... shall be rounded up to only two significant figures: 2.0: 3.0 = 0.67 (two significant figures, ie, 6 and 7).

   Example 2: 2.1: 3.0 = .... ?significant figure is at least two. If you use the calculator then the result is 0.7. Must be written to zero so there are two significant figures. 2.1: 3.0 = 0.70 (two significant figures, which is 7 and 0)

   Rules addition and reduction of significant figures

   "In addition or subtraction, the result should not be more accurate than the least accurate figures."

   Example 1: 3.7 to 0.57 = ...?3.7 the least accurate. If using a calculator, the result is 3.13. These results are more accurate than 3.7 therefore be rounded to 3.1. 3.7-.57 = 3.1

   Example 2: 10.24 + 32.451 = ......?10.24 least accurate. If using a calculator, the result is 42.691. These results are more accurate than 10.24 should therefore be rounded to: 42.69. 10.24 + 32.451 = 42.69

   Example 3: 10.24 + 32.457 + 2.6 = .... ?2.6 the least accurate. If added together, the result is 45.297. These results are more accurate than 2.6 therefore be rounded to 45.3. 10.24 + 32.457 + 2.6 = 45.3Or at least many significant figures in the result of addition or subtraction has no effect.