The answers section in my book gives let statements that always have significant digits. However, it never seems to take mass into consideration. For example, if everything in the question has 3 sig digs and the mass is 2000kg, the final answer will have 3 sig digs. If everything in the question has 3 sig digs and the mass is 250kg, the final answer will still have 3 sig digs. I'm a little confused as to why there is an "exception'. I thought you were supposed to use the lowest number of significant digits given in the question for your final statements. Is my book wrong or is there a reason for this? Also, do degrees have any affect on significant digits?