Three six faced dice are tossed together, then the probability that exactly two of the three numbers are equal is:

165/216 177/216 51/216 90/216

90/216

P(exactly 2 matches occur) = $(\frac{1}{6}.\frac{1}{6}.\frac{5}{6}).{^6C}_1.{^3C}_2=\frac{90}{216}$