The answer is 2 .
simplify log(down)10 (1/100) : -2
apply log rule : -log(down)10 (100)
rewrite 100 in power-base form : -log(down)10 (10^2)
apply log rule again : -2log(down)10 (10)
apply one more time : -2*1
Multiply : -2
refine from -(-2) = 2
I hope this helps