Question 1064580
log 0.728=x
Assume base 10.
Solve for x.

Here is how I solved this problem:

log 0.728 is equivalent to 10^x=0.728
since N is less than 1
characteristic is less than 1
so c is negative = 0+1=1 with a negative sign placed on top of 1. Thus the value of X will begin with 1.something. 
That something is the mantissa obtained from appendix of a math textbook based on number 728 and mantissa is 8621.  
Conclusion: x=1.8621 with a bar over digit 1 signifying it's negative number. Therefore, log0.728=x= -1.8621

CONTROVERSY:
WHEN I PLUG IN MY CALCULATOR LOG 0.728, THE ANSWER IS NOT -1.8621, BUT -0.1379. SO CALCULATOR SAYS, THE ANSWER IS -0.1379 AND MY CALCULATION SAYS THE ANSWER IS -1.8621. THE BOOK ALSO SAYS THAT THE ANSWER IS EITHER -1.8621 OR 9.8621-10=-0.1379.

COULD YOU PLEASE TELL ME WHAT DO THOSE DIFFERENT ANSWERS MEAN AND WHY ARE THEY ALL CORRECT ANSWERS? HOW CAN -1.8621 BE CORRECT AT THE SAME TIME WITH -0.1379 AND ALSO WITH 9.8621-10?
-------------
There's no controversy.
log(0.728) = -0.1379 = 0.8621 - 1
------
It was necessary to deal with the characteristic and the mantissa when using tables, but not now.