One Crazy Summer by Rita Williams-Garcia

I finally got around to reading this Newbery Honor book, and I'm glad I did! Delphine is eleven, and is used to "mothering" her younger sisters. Their own mother left them when Fern, the youngest, was a newborn baby, and now the three sisters are flying on their own to California to visit a mother they haven't seen or heard from since that day. Cecile didn't want her kids then, and she doesn't want them now, and it's up to Delphine to make sure they get fed (though Cecile won't let them in her kitchen) and stay out of trouble (though Cecile sends them to the Black Panthers center every day to get them out of her way). It's the final straw, though, when Cecile is arrested with two members of the Black Panthers, and Delphine and her sisters are really on their own.