Answer
$A\cap D$
$6$
Work Step by Step
$A$: the red die shows 1.
$D$: the numbers do not add to 11
The red die shows 1 but (and) the numbers do not add to 11: $A\cap D$
$A\cap D=${(1,1),(1,2),(1,3),(1,4),(1,5),(1,6)}
(The first number is the red die, and the second is the green)
$n(A\cap D)=6$