Let $A = \{1, 2, 3, 4, 5, 6\}$ and $R = \{(x, y) : y = x + 1, x, y \in A\}$. The relation $R$ in roster form is:

Pairs with $y = x + 1$ and both $x, y \in \{1,\ldots,6\}$: $(1,2),(2,3),(3,4),(4,5),(5,6)$. The pair $(6,7)$ is excluded because $7 \notin A$.