I do not fully understand significant figures. It seems the physics textbooks ignore their own significant figure rules, eventually. For this problem when I divide 2.3 m by 1.0 s, I get 2.3 m/s, but the answer in the book is 2.30 m/s. In another situation I am divding 48.3 m by 3.0 s to get 16.1 m/s, then I round to get 16 m/s, but the text shows 16.1 m/s as the final answer. Also, what is this thing I have heard of where the 0 in the ones place of the decimal can be significant - I heard this applies when the device can measure that 'ones' place but it happened to be 0( i.e. 0.1 meter). I have a much easier solution to solve this problem. Can someone just list all the special-case significant figure rules(including the rules derived from the fundamental ones)?