Q: Let S = {1,2,5,6 }
Define a relation R on S of at least four order pairs, as (a,b) R iff a*b is even (i.e. a multiply by b is even)
Since multiplying any integer by an even integer results in an even integer, you just need to make sure that if (x,y) is in R, then at least one of x or y is even. For example, it would be okay to have (2,5) in R, but it wouldn't be okay to have (1,5) in R. There are lots of choices for R here. For example, we could let R={(1,2),(2,1),(2,2),(2,5)}.
You asked for our help, did you not?
Then you demand a different more "standard" answer. I asked who you were to do that.
Then I gave you the complete answer that accounted for the 'iff' part of your question.
But you seem to not understand even that correct answer.
Please be more attentive to correct answers in the future.