FOR MIDDLE SCHOOLERS: IXL Learning has just launched adaptive science and social studies content for grades 6–8. According to IXL, the content is organized in a way that moves students through various stages of a skill; at each stage, students first learn factual knowledge, and then practice by analyzing examples and visual or written primary sources. IXL first launched adaptive science and social studies content back in June of 2016, when the company released offerings for grades 2-5.