Question

Let R be a relation on the set A={1,2,3,4,5,6} defined by R= {(a,b):a+b is less than or equal to 9}. What are the elements of R?

Answer 1

$R=\{ (1,1), (1,2), (1,3), (1,4), (1,5), (1,6),$

$(2,1),(2,2), (2,3), (2,4), (2,5), (2,6),$

$(3,1), (3,2), (3,3), (3,4), (3,5), (3,6),$

$(4,1), (4,2), (4,3), (4,4), (4,5),$

$(5,1), (5,2), (5,3), (5,4),$

$(6,1), (6,2), (6,3)\}$