Should I continue trying with these two girls?

I'm in my first year at college, and I didn't know anyone to begin with so I'm trying to make some new friends. I'm also hoping to get good grades, and I'm studying quite a bit. I met two girls at the start of semester who I thought were nice, and we hung out because they're in my class. Exams are coming up soon, and my professor is making us work really hard in class. He often puts us in groups to complete activities. He puts me with these girls, and I don't know why, but all they do now is just sit there playing on their iPhones while we should be working. Both of them. I find it rude. I say something to them and they ignore me and don't contribute. They do not even look at me, they just go on Facebook or start texting. Then the professor comes over to ask how we're doing with the activity… And it's embarrassing because I do the talking and then usually get the answer wrong because we haven't worked together to figure it out. He probably thinks I'm an idiot or something. I care about my grades and what he thinks. Why do they play on their phones? It's So rude, I'd never do that if someone was talking to me. What should I do?

You should discuss this privately with your professor to see if you can work something out. The girls probably don't care if there are put with someone else since they act like phone zombies.