P⃗+Q⃗=Q⃗+P⃗\vec{P}+\vec{Q}=\vec{Q}+\vec{P}P+Q=Q+P
(P⃗+Q⃗)+R⃗=P⃗+(Q⃗+R⃗)(\vec{P}+\vec{Q})+\vec{R}=\vec{P}+(\vec{Q}+\vec{R})(P+Q)+R=P+(Q+R)
m(P→+Q→)=mP→+mQ→\mathrm{m}(\overrightarrow{\mathrm{P}}+\overrightarrow{\mathrm{Q}})=\mathrm{m} \overrightarrow{\mathrm{P}}+\mathrm{m} \overrightarrow{\mathrm{Q}}m(P+Q)=mP+mQ
P→−Q→=P→+(−Q→)\overrightarrow{\mathrm{P}}-\overrightarrow{\mathrm{Q}}=\overrightarrow{\mathrm{P}}+(-\overrightarrow{\mathrm{Q}})P−Q=P+(−Q)