Significant Figures in the result of Addition or Subtraction
The result must be expressed with the same absolute uncertainty
                                          found in the least precisely   determined quantity used to obtain the result.
               (You may show no more digits to the right of the decimal point in the result
than is found in  the factor having the fewest number of digits to the right of the decimal point)
     25.6854 g  
+                                           
25.86 g
round off to two decimal places
implied precision
± 0.0001g
 ±   0.01
± 0.0001g
(± 0.01g)
25.8554  g                                     
0.17 g                                    
0.17 g                                    
 ±   0.01