7. Toss a die twice, observe the numbers facing up, the probability that the product of the two numbers is a multiple of 3 is
7. $\frac{5}{9}$ Detailed Explanation: The product of two numbers being a multiple of 3 includes the following basic events: $(1,3)(2,3)(3,3)(4,3)(5,3)(6,3),(1$,
6) $(2,6)(3,6)(4,6)(5,6)(6,6),(3,1)(3,2)(3,4)(3,5),(6,1)(6,2)(6,4)(6,5)$, a total of 20. Therefore, the probability that the product of two numbers is a multiple of 3 is $\frac{20}{36}=\frac{5}{9}$.