-log(0.05)

-log(0.05) ?

$$\small{\text{$ \begin{array}{rcl} -\log_{10}{(0.05)} &=& \log_{10}{(1)} - \log_{10}{(0.05)} \qquad | \qquad \log_{10}{(1)} =0 \\ \\ \log_{10}{(1)} - \log_{10}{(0.05)} &=& \log_{10}{ \left(\dfrac{1}{0.05} \right) }\\\\ &=& \log_{10}{ \left(\dfrac{100}{5} \right) }\\\\ &=& \log_{10}{(20)}\\\\ &=& \log_{10}{(2\cdot 10)}\\\\ &=& \log_{10}{(2)}+\log_{10}{10)} \qquad | \qquad \log_{10}{(10)} =1\\\\ &=& \log_{10}{(2)}+1\\\\ &=& 1+\log_{10}{(2)}\\\\ &=& 1+0.30102999566\\\\ -\log_{10}{(0.05)} &=& 1.30102999566\\\\ \end{array} $}}$$