All the possibilities of two tosses are:
H - H
H - T
T - H
T - T
Probabilities:
no Heads . . . 0.25
no Tails . . . . . 0.25
one Heads . . . 0.5
one Tails . . . . . 0.5
two Heads . . . 0.25
two Tails . . . . . 0.25
at least one Heads . . . 0.75
at least one Tails . . . . . 0.75
the two results are the same . . . 0.5
the two results are different . . . 0.5