The sum of two vectors is always \vec{A}+\vec{B}.

For example: if \vec{B}=-0.2 \vec{A}
\vec{A}+\vec{B}=\vec{A}+ (-0.2\vec{A})=0.8 \vec{A} (1.0-0.2)

if\vec{B}= 0.2 \vec{A} , two vector are parallel.
\vec{A}+\vec{B}=\vec{A}+ (0.2\vec{A})=1.2 \vec{A} (1.0+0.2)