More precise on "element", "number" and "set"

Some of the formulations are confusing. In the second set: "Any element smaller than this element". Let's use different words for different things. In this particular case, there are smaller numbers than sqrt(3) that satisfy x^2 > 3, eg -100. Same for the third case. The explanation for the last set is also confusing: "the set" sometimes refers to the entire intersection, sometimes to one of the sets in the intersection.

Should be good now - I wrote it in a rush but I think its better.