lg25 + (2/3)lg8 + lg5 * lg20 + (lg2)^2
= lg25 + lg8^(2/3) + lg5 * lg(10×2）+ (lg2)^2
= lg25 + lg64^(1/3) + lg5*(1 + lg2) + (lg2)^2
= lg25 + lg4 + lg5 + lg2(lg5 + lg2)
= lg(25×4) + lg(5×2)
= lg100 + lg10
= 2 + 1 = 3