•1.All nonzero digits are significant  965       12,456      3.41567
 
 •Zeroes may be troublesome.
  
 •2. Zeroes btn 2 nonzero digits are sig.  10.143     20006     230807   3.00001
 •3. Zeroes that come before the first nonzero digit (after the decimal pt) are not
 sig.   0.000000045  (4.5
 x 10-8)
 •