Consider number $2$ $and$ $3$. There is a relation between these numbers that later one (3) is just 1 greater then first one (2). I can represent this sentence like this: $3$ **R** $2$, Where **R** mean "greater then" . Now there is another notation like (3,2) ∈ **R**. ***[Here in ordered pair first element is greater then second element].***
Here I having problem. In first notation **R** simply mean "greater then" but in second notation we are considering **R** to be a set. How could "greater then" be a set? 
Pardon me if this seems stupid. But I would be grateful if you consider explaining where I am doing mistake. Thanks