Alright I haven’t done this in a while but I’ll try.
When doing slope you always want to do rise over run. Slope= y2-y1/ x2- x1.
So what you want to do is find your two pretty points on the graph! Meaning where the point is exactly on those little corners!
So if we start you can see you rise 2 spaces up before you’re vertical to your next pretty point. Next you want to RUN to the next one which would give you 4!
This being said you’re slope is 2/4 but you want to make sure you simplify if you can! In this case you can do it’ll give 1/2!
Again I haven’t done this in a while and I apologize if this is wrong! Hope this helps!