how to understand log table 


 

suppose your calculation is 8231/1245
then first take 8231 there are 4 digits so characterstick is 3
now search for log of 8231
the log will be in format 3.log of 8231
similarly find log of 1245
its log will also be 3.something
then substract log of 8231 from log of 1245
suppose your answer is 0.7832
find its antilog
and the number gained is your answer