355D: Girl Spends Day With Mom, Boy Spends Day With Dad

I’m looking for a children’s book that I had in the mid 1970’s.  It was a hardcover book and I believe it was oversized.  The ‘first’ story was about a child (believe it was a girl) spending the day with her mommy.  You then flipped the book upside down & over and there was a ‘second’ story about the child spending the day with his/her daddy and they went to the zoo.  I remember a picture of them looking in the animal exhibit and the child is holding a balloon and I think they get ice cream.  I’m pretty sure it’s people and not animals (i.e. not the Mercer Meyer little critter book).