You already know the roll was even and now ask whether it's a 6, shrinking the stage down to just the even outcomes, P(B|A) = P(A∩B)/P(A)
Module goal. Tell apart "they don't affect each other" from "knowing one, now look at the other," and master the multiplication, conditional, and total probability rules
eastmath.com · 33.4 Independence and Conditional Probability · 33.4.2 Conditional Probability