Question

a recipe for a pie calls for 1/3 cup of blackberries and 2/6 cup of rasberries needed for the recipe ?

Answer 1

question doesn't make sense...do you mean how many berries in total required?

If yes, then:
1/3 + 2/6
find a common denominator
= 2/6+2/6
=4/6
=2/3 cups