=lg0.45/lg2
=lg(45*0.01)/lg2
=(lg45+lg0.01)/lg2
=(lg(5*9)-2)/lg2
=(lg5+lg9-2)/lg2
=(lg10/2+2lg3-2)/lg2
=(1-lg2+2lg3-2)/lg2
=(2lg3-lg2-1)/lg2
=(2*0.4771-0.3010-1)/0.3010
=-1.1522