Or 9.58- 4.72= 4.86. Dividing by 2.5, 4.86/2.5= 1.944 and since the 2.5 is negative, that is -1.944. The only one you really need a calculator for is \(\displaystyle 10^{-1.944}= 0.01137627285823430850366472770741\) which is rounded to 0.011. In years B.C. (before calculators), you would have looked up the "anti-logarthm" of -1.944 in a table of logarithms.[/tex]