CK-12 FlexBook 2.0 vs Formative

CK-12 FlexBook 2.0 provides customizable digital textbooks for K–12 subjects including science, math, and social studies. Lessons can combine text with PLIX interactives, simulations, adaptive practice, and related learning materials. Adaptive Practice draws questions from a library of more than 150,000 and adjusts selections based on student answers. Teachers can assign lessons, videos, interactives, and practice to whole classes or differentiated groups, then view progress reports. Educators can reorder chapters and edit or add content in customized FlexBooks. The service works in browsers on laptops, desktops, Chromebooks, tablets, and mobile devices, and is listed at free. Standalone Simulations and PLIX Interactives require a tablet-size screen or larger. Users may download PDFs of FlexBooks they create or customize, though interactive content may not render; CK-12-created PDFs are not downloadable. CK-12 says it is still converting all core content to FlexBook 2.0. Listed SSO or LMS partners include Google Classroom, Canvas, Schoology, Kiddom, Clever, and ClassLink.

Formative is a web platform for creating interactive lessons, assigning assessments, and seeing student progress as responses arrive. It serves individual teachers, schools, districts, and K-12 students across subjects. Luna AI can generate standards-aligned activities from prompts, PDFs, or documents, then provide hints and feedback. More than 20 technology-enhanced question types and multimedia formats support varied assessments. Teachers receive live response data to identify misconceptions and adjust instruction during learning. Integrations with Google Classroom, Clever, ClassLink, Canvas, and other LMS or SIS systems support rostering, single sign-on, and assignment syncing. Formative says it complies with FERPA, COPPA, and other K-12 privacy standards; student information is not sold, and student work is not sent to a public chatbot. Access requires a current Chrome, Firefox, or Safari browser and stable high-speed internet. The Free Teacher plan costs nothing. Classroom Plan costs $20.75 a month, billed annually, and a 14-day trial is listed. There is no stated limit on students added to a class.