JACKSON, Miss. — LeMya Vaughn, wearing a pink shirt, her hair braided neatly, sat in a large red armchair, her feet swinging far above the floor, practicing her reading skills. She leaned in toward her laptop and looked at a sentence that read, “Bake me a cake.” The word “bake” was in red. The rest of the words were in white. “Click on a colored word,” said a cheerful voice from the computer. LeMya’s mother, Lakesha Vaughn, sat close by watching as her daughter considered which word to click on.