$1 \div 0.2=\frac{1}{0.2}=\frac{10}{2}=5 ; 0 . \overline{2}=0.222 \ldots . . ;(0.2)^{2}=0.04$. $$0.04<0.2<0.22 \ldots \ldots<5 .$$ Since 0.04 is the least, so $(0.2)^{2}$ is the least.
Explanation as extracted from the printed page; notation may be imperfect.