We have the angular momentum quantum numbers $(j,l,s)$ representing total angular momentum, orbital angular momentum and spin respectively.
I am solving a problem where we try to show that if you have two spin-1 particles then $l+s$ is even. I didn't understand how to relate these numbers together to be able to show this, so I tried to look at some Wikipedia pages, such as this one. I saw a relation which I thought may help solve the problem: $j=|l\pm s|$. However, I don't understand this equation - which value do you take, $+$ or $-$?
Does this help solve my problem? If so can someone explain the $\pm$ part?
If not, could someone guide me towards something that will help me solve the problem? An equation or relation perhaps, or a hint?