The looks of annoyed disbelief passed across the best friends' faces.
The problem with this is that you're telling us they are annoyed, when you instead should be showing us.
Instead of just saying they are annoyed, show it like this:
Ex: Anna stomped her foot on the floor as she tightened her fists. Evie wore a tight frown as she followed Anna with a stomp....
You get the idea. I never actually said they were annoyed, but it's apparent from their actions.
Sam was smart, but she wasn't smart enough to help out Anna anymore. She zipped through all her work, just from reading the book's explanations about each form of math. For the past weeks, she'd been skimming back over the algebra books, refreshing her memory and taking all the review tests in the back pages. One of her favorite things was helping the little girls with their easy math. Evie was still in the middle of her algebra book.
Same thing here. Don't just tell us they're smart. The reader might not believe you (silly, I know) but if you show, there is no reason for the reader not to think Anna's smart. An example would be turning this into a scene by itself in which Sam asks a question and Anna gets it right within seconds, while on another question Evie struggles when she is called on. Doing it this way makes everything more vivid and believable.
Her expression was that of disbelief.
Again, show us how she's in disbelief (ex: eyes wide, mouth hanging open etc.)
Evie remembered when Jackie finished all her books, but that was at least four years ago. The next week, she was adopted by a couple who couldn't have children and felt sorry for Jackie being so couped up with such young girls.
You're infodumping too much about the past. It's breaking the action and makes the reader lose interest. If the information is not absolutely relevant to the story's conflict, please cut it out. Random bits of info will do nothing but distract your readers.
Anna raised an eyebrow. "Because I'm smart?" she asked
sarcastically,
Since you mentioned her raised eyebrow, her tone becomes clear. You don't need to mention "sarcastically".
The ending was good, you have interesting conflicts going on. I liked how at the end she adopted them both, it gives a warm feeling
Hope that helps,
Tony
