Meaning of "per digit" for a sensor reading
The g means the acceleration of gravity, 9.8 m/s^2.  You can set 5 ranges.  The highest range is the least sensitive at 0.732*9.8 m/s^2 for each LSB.  There are 4 ranges of magnetic measurement.  You pick the one you want, plus or minus 2,4,8, or 12 Gauss.  Once you pick the range, the sensitivity tells you how magnetic flux density it take to increase the count by one.  For the 12 Gauss range it takes .48mGauss to change the output by one.  There are three ranges of angular measurement.  The highest is 2000 degrees/second.  When set to this range it takes 0.070 degrees per second to change the output by 1 count.