High school math probability questions, online waiting

3 same: first take a class from 13 types of cards have C(13,1) then take three from this class have C(4,3) i.e.: C(13,1)*C(4,3)

2 same: before taking a class there are still 12 types, according to the above method have C(12,1)*C(4,2)

Can be obtained that P=C(13,1)*C(4,3)*C (12,1)*C(4,2)/C(52,5)=6/4165