[deprosun]

The ternary relation TImes(i, j, k) to be the relation corresponding to the predicate "i times j equals k". This relation on the base set {0, 1, 2, 3, 4}. How many elements does the relation have?

Is there an easier way to count the number of elements rather than "doing it all out"? If so, how?

[sepp2k]

If you have a fixed i and a fixed j, how many k can exist at most such that Times(i,j,k)? Will there always be at least one such k? If not, under which conditions will there be no k for a given i and j?

Answering those questions should lead you to some shortcuts you can use instead going through all 5³ combinations.

[deprosun]

Oh, I had this question in my Probability class. You're right! thanks:)