Santiago is trying to show his teacher why the product of two rational numbers is another rational number. his first steps are shown. which is the best method santiago could use to continue?
test with m = 1, n = 2, p = 3, and q = 4. since 12 and 34 are both rational, it is clear that the statement is true.

mn × pq = m×pn×q
show that mp and nq are both integers.

mn × pq = m×pn×q
show that mn and pq are all integers.

since mn is rational and pq is rational, then mn × pq must be rational.