Answer from cs61c-cg (Daniel Lau 16776873) for Question 1
c5 = g4 + p4 . c4
where c4 = g3 + (p3 . g2) + (p3. p2. g1) + (p3. p2 . p1 . g0) + (p3 . p2 . p1 . p0 . c0)